Sync Translation Files

package.json

{
  "name": "example",
  "version": "1.0.0",
  "private": true,
  "scripts": {
    "start": "react-scripts start",
    "sync:i18n": "ts-node --project ../scripts/tsconfig.json ../scripts/syncTranslations.ts",
    "build": "react-scripts build",
    "test": "react-scripts test"
  }
}

syncTranslations.ts

import fs from "fs";
import { join } from "path";
import prettier from "prettier";
import english from "../locales/common_en-US.json";
import { traverseTranslations } from "./traverseTranslations";

const paths = traverseTranslations();

const set = (string: string, obj: any, value: string) => {
  const [current, ...rest] = string.split(".");
  rest.length >= 1
    ? set(rest.join("."), (obj[current] = obj[current] || {}), value)
    : (obj[current] = value);
  return obj;
};

const get = (object: any, path: string, defval = undefined) => {
  return path
    .split(".")
    .reduce((xs, x) => (xs && xs[x] ? xs[x] : defval), object);
};

export interface IHash {
  [locale: string]: number;
}

let missingKeys: IHash = {};

fs.readdirSync(join(__dirname, "../locales")).forEach((locale) => {
  if (locale === "common_en-US.json") {
    return; // No need to analyse the master file
  }

  const filename = join(__dirname, "../locales", locale);

  let data: any;

  try {
    data = JSON.parse(fs.readFileSync(filename, { encoding: "utf-8" }));
  } catch (err: any) {
    throw new Error(`${locale}: ${err.message}`);
  }

  paths.forEach((p) => {
    if (get(data, p, undefined) === undefined) {
      set(p, data, get(english, p, undefined));
      missingKeys[locale] = missingKeys[locale] ? missingKeys[locale] + 1 : 1;
    }
  });

  fs.writeFileSync(
    filename,
    prettier.format(JSON.stringify(data), {
      parser: "json",
    })
  );
});

console.log("NEW TRANSLATIONS REQUIRED:");
console.log(missingKeys);

traverseTranslations.ts

import translations from "../locales/common_en-US.json";

const keys: string[] = [];

type TranslationRecord = {
  [P in string]: string | TranslationRecord;
};

const _traverseTranslations = (obj: TranslationRecord, path: string[]) => {
  Object.keys(obj).forEach((key) => {
    const objOrString = obj[key];
    if (typeof objOrString === "string") {
      keys.push([...path, key].join("."));
    } else {
      _traverseTranslations(objOrString, [...path, key]);
    }
  });
};

export const traverseTranslations = () => {
  _traverseTranslations(translations, []);
  return keys;
};

tsconfig.json

{
  "compilerOptions": {
    "target": "es6",
    "module": "commonjs",
    "lib": ["dom", "es6", "es2017", "esnext.asynciterable"],
    "sourceMap": true,
    "outDir": "./dist",
    "moduleResolution": "node",
    "removeComments": true,
    "noImplicitAny": true,
    "strictNullChecks": true,
    "strictFunctionTypes": true,
    "noImplicitThis": true,
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "noImplicitReturns": true,
    "noFallthroughCasesInSwitch": true,
    "allowSyntheticDefaultImports": true,
    "esModuleInterop": true,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "resolveJsonModule": true,
    "baseUrl": "."
  },
  "exclude": ["node_modules"],
  "include": ["./*.ts"]
}