ES7 Object.entries() in TypeScript not working

Question

I have an issue with transpiling ES7 code with TypeScript. This code:

const sizeByColor = {
    red: 100,
    green: 500,
};

for ( const [ color, size ] of          


        

Answer 1

If you don't want to include the full set of ECMAScript 2017 (ES8) in your set of libraries, then you can also use es2017.object to just satisfy the resolution of Object.entries and related.

Here is a minimal working example:

src/index.ts

const sizeByColor = {
  red: 100,
  green: 500,
};

for (const [color, size] of Object.entries(sizeByColor)) {
  console.log(color);
  console.log(size);
}

tsconfig.json

{
  "compilerOptions": {
    "lib": ["dom", "es2016", "es2017.object"],
    "rootDir": "src",
    "target": "es6",
    "outDir": "dist"
  },
  "exclude": [
    "node_modules"
  ]
}

Note: If "target" is set to "es6", then TypeScript uses by default the following "lib" entries (if none are specified): ["dom", "dom.iterable", "es6", "scripthost"].

The library defaults get overwritten when setting "lib" manually, that's why I needed to add "dom" (to use console.log in my code) and "es6" to demonstrate the usage of ES6 and partial ES8 ("es2017.object").

Source: TypeScript Compiler Options