409 lines
9.1 KiB
JavaScript
409 lines
9.1 KiB
JavaScript
/*
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JSON-to-Go
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by Matt Holt
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https://github.com/mholt/json-to-go
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A simple utility to translate JSON into a Go type definition.
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*/
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function jsonToGo(json, typename, flatten = true)
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{
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let data;
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let scope;
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let go = "";
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let tabs = 0;
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const seen = {};
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const stack = [];
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let accumulator = "";
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let innerTabs = 0;
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let parent = "";
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try
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{
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data = JSON.parse(json.replace(/\.0/g, ".1")); // hack that forces floats to stay as floats
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scope = data;
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}
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catch (e)
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{
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return {
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go: "",
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error: e.message
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};
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}
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typename = format(typename || "AutoGenerated");
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append(`type ${typename} `);
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parseScope(scope);
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return {
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go: flatten
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? go += accumulator
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: go
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};
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function parseScope(scope, depth = 0)
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{
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if (typeof scope === "object" && scope !== null)
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{
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if (Array.isArray(scope))
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{
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let sliceType;
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const scopeLength = scope.length;
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for (let i = 0; i < scopeLength; i++)
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{
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const thisType = goType(scope[i]);
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if (!sliceType)
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sliceType = thisType;
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else if (sliceType != thisType)
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{
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sliceType = mostSpecificPossibleGoType(thisType, sliceType);
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if (sliceType == "interface{}")
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break;
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}
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}
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const slice = flatten && ["struct", "slice"].includes(sliceType)
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? `[]${parent}`
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: `[]`;
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if (flatten && depth >= 2)
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appender(slice);
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else
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append(slice)
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if (sliceType == "struct") {
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const allFields = {};
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// for each field counts how many times appears
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for (let i = 0; i < scopeLength; i++)
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{
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const keys = Object.keys(scope[i])
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for (let k in keys)
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{
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let keyname = keys[k];
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if (!(keyname in allFields)) {
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allFields[keyname] = {
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value: scope[i][keyname],
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count: 0
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}
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}
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else {
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const existingValue = allFields[keyname].value;
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const currentValue = scope[i][keyname];
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if (compareObjects(existingValue, currentValue)) {
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const comparisonResult = compareObjectKeys(
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Object.keys(currentValue),
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Object.keys(existingValue)
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)
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if (!comparisonResult) {
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keyname = `${keyname}_${uuidv4()}`;
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allFields[keyname] = {
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value: currentValue,
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count: 0
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};
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}
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}
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}
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allFields[keyname].count++;
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}
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}
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// create a common struct with all fields found in the current array
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// omitempty dict indicates if a field is optional
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const keys = Object.keys(allFields), struct = {}, omitempty = {};
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for (let k in keys)
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{
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const keyname = keys[k], elem = allFields[keyname];
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struct[keyname] = elem.value;
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omitempty[keyname] = elem.count != scopeLength;
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}
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parseStruct(depth + 1, innerTabs, struct, omitempty); // finally parse the struct !!
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}
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else if (sliceType == "slice") {
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parseScope(scope[0], depth)
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}
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else {
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if (flatten && depth >= 2) {
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appender(sliceType || "interface{}");
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} else {
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append(sliceType || "interface{}");
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}
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}
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}
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else
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{
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if (flatten) {
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if (depth >= 2){
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appender(parent)
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}
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else {
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append(parent)
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}
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}
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parseStruct(depth + 1, innerTabs, scope);
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}
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}
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else {
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if (flatten && depth >= 2){
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appender(goType(scope));
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}
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else {
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append(goType(scope));
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}
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}
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}
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function parseStruct(depth, innerTabs, scope, omitempty)
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{
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if (flatten) {
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stack.push(
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depth >= 2
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? "\n"
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: ""
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)
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}
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if (flatten && depth >= 2)
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{
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const parentType = `type ${parent}`;
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const scopeKeys = formatScopeKeys(Object.keys(scope));
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// this can only handle two duplicate items
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// future improvement will handle the case where there could
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// three or more duplicate keys with different values
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if (parent in seen && compareObjectKeys(scopeKeys, seen[parent])) {
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stack.pop();
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return
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}
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seen[parent] = scopeKeys;
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appender(`${parentType} struct {\n`);
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++innerTabs;
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const keys = Object.keys(scope);
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for (let i in keys)
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{
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const keyname = getOriginalName(keys[i]);
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indenter(innerTabs)
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const typename = format(keyname)
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appender(typename+" ");
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parent = typename
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parseScope(scope[keys[i]], depth);
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appender(' `json:"'+keyname);
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if (omitempty && omitempty[keys[i]] === true)
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{
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appender(',omitempty');
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}
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appender('"`\n');
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}
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indenter(--innerTabs);
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appender("}");
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}
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else
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{
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append("struct {\n");
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++tabs;
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const keys = Object.keys(scope);
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for (let i in keys)
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{
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const keyname = getOriginalName(keys[i]);
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indent(tabs);
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const typename = format(keyname);
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append(typename+" ");
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parent = typename
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parseScope(scope[keys[i]], depth);
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append(' `json:"'+keyname);
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if (omitempty && omitempty[keys[i]] === true)
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{
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append(',omitempty');
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}
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append('"`\n');
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}
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indent(--tabs);
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append("}");
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}
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if (flatten)
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accumulator += stack.pop();
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}
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function indent(tabs)
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{
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for (let i = 0; i < tabs; i++)
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go += '\t';
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}
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function append(str)
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{
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go += str;
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}
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function indenter(tabs)
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{
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for (let i = 0; i < tabs; i++)
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stack[stack.length - 1] += '\t';
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}
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function appender(str)
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{
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stack[stack.length - 1] += str;
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}
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// Sanitizes and formats a string to make an appropriate identifier in Go
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function format(str)
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{
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if (!str)
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return "";
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else if (str.match(/^\d+$/))
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str = "Num" + str;
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else if (str.charAt(0).match(/\d/))
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{
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const numbers = {'0': "Zero_", '1': "One_", '2': "Two_", '3': "Three_",
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'4': "Four_", '5': "Five_", '6': "Six_", '7': "Seven_",
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'8': "Eight_", '9': "Nine_"};
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str = numbers[str.charAt(0)] + str.substr(1);
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}
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return toProperCase(str).replace(/[^a-z0-9]/ig, "") || "NAMING_FAILED";
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}
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// Determines the most appropriate Go type
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function goType(val)
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{
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if (val === null)
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return "interface{}";
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switch (typeof val)
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{
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case "string":
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if (/\d{4}-\d\d-\d\dT\d\d:\d\d:\d\d(\.\d+)?(\+\d\d:\d\d|Z)/.test(val))
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return "time.Time";
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else
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return "string";
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case "number":
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if (val % 1 === 0)
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{
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if (val > -2147483648 && val < 2147483647)
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return "int";
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else
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return "int64";
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}
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else
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return "float64";
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case "boolean":
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return "bool";
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case "object":
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if (Array.isArray(val))
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return "slice";
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return "struct";
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default:
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return "interface{}";
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}
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}
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// Given two types, returns the more specific of the two
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function mostSpecificPossibleGoType(typ1, typ2)
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{
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if (typ1.substr(0, 5) == "float"
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&& typ2.substr(0, 3) == "int")
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return typ1;
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else if (typ1.substr(0, 3) == "int"
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&& typ2.substr(0, 5) == "float")
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return typ2;
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else
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return "interface{}";
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}
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// Proper cases a string according to Go conventions
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function toProperCase(str)
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{
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// https://github.com/golang/lint/blob/5614ed5bae6fb75893070bdc0996a68765fdd275/lint.go#L771-L810
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const commonInitialisms = [
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"ACL", "API", "ASCII", "CPU", "CSS", "DNS", "EOF", "GUID", "HTML", "HTTP",
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"HTTPS", "ID", "IP", "JSON", "LHS", "QPS", "RAM", "RHS", "RPC", "SLA",
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"SMTP", "SQL", "SSH", "TCP", "TLS", "TTL", "UDP", "UI", "UID", "UUID",
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"URI", "URL", "UTF8", "VM", "XML", "XMPP", "XSRF", "XSS"
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];
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return str.replace(/(^|[^a-zA-Z])([a-z]+)/g, function(unused, sep, frag)
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{
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if (commonInitialisms.indexOf(frag.toUpperCase()) >= 0)
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return sep + frag.toUpperCase();
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else
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return sep + frag[0].toUpperCase() + frag.substr(1).toLowerCase();
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}).replace(/([A-Z])([a-z]+)/g, function(unused, sep, frag)
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{
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if (commonInitialisms.indexOf(sep + frag.toUpperCase()) >= 0)
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return (sep + frag).toUpperCase();
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else
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return sep + frag;
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});
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}
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function uuidv4() {
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return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
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var r = Math.random() * 16 | 0, v = c == 'x' ? r : (r & 0x3 | 0x8);
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return v.toString(16);
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});
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}
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function getOriginalName(unique) {
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const reLiteralUUID = /^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i
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const uuidLength = 36;
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if (unique.length >= uuidLength) {
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const tail = unique.substr(-uuidLength);
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if (reLiteralUUID.test(tail)) {
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return unique.slice(0, -1 * (uuidLength + 1))
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}
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}
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return unique
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}
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function compareObjects(objectA, objectB) {
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const object = "[object Object]";
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return Object.prototype.toString.call(objectA) === object
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&& Object.prototype.toString.call(objectB) === object;
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}
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function compareObjectKeys(itemAKeys, itemBKeys) {
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const lengthA = itemAKeys.length;
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const lengthB = itemBKeys.length;
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// nothing to compare, probably identical
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if (lengthA == 0 && lengthB == 0)
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return true;
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// duh
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if (lengthA != lengthB)
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return false;
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for (let item of itemAKeys) {
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if (!itemBKeys.includes(item))
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return false;
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}
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return true;
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}
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function formatScopeKeys(keys) {
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for (let i in keys) {
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keys[i] = format(keys[i]);
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}
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return keys
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}
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}
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if (typeof module != 'undefined') {
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if (!module.parent) {
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process.stdin.on('data', function(buf) {
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const json = buf.toString('utf8')
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console.log(jsonToGo(json).go)
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})
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} else {
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module.exports = jsonToGo
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}
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}
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