Importing JSON file in TypeScript

Question

I have a JSON file that looks like following:

{

  "primaryBright":    "#2DC6FB",
  "primaryMain":      "#05B4F0",
  "primaryDarker":    "#04A1D7",
  "primaryDarkest":   "#048FBE",

  "secondaryBright":  "#4CD2C0",
  "secondaryMain":    "#00BFA5",
  "secondaryDarker":  "#009884",
  "secondaryDarkest": "#007F6E",

  "tertiaryMain":     "#FA555A",
  "tertiaryDarker":   "#F93C42",
  "tertiaryDarkest":  "#F9232A",

  "darkGrey":         "#333333",
  "lightGrey":        "#777777"
}

I'm trying to import it into a .tsx file. For this I added this to the type definition:

declare module "*.json" {
  const value: any;
  export default value;
}

And I'm importing it like this.

import colors = require('../colors.json')

And in the file, I use the color primaryMain as colors.primaryMain. However I get an error:

Property 'primaryMain' does not exist on type 'typeof "*.json"

Answer 1

With TypeScript 2.9.+ you can simply import JSON files with benefits like typesafety and intellisense by doing this:

import colorsJson from '../colors.json'; // This import style requires "esModuleInterop", see "side notes"
console.log(colorsJson.primaryBright);

Make sure to add these settings in the compilerOptions section of your tsconfig.json (documentation):

"resolveJsonModule": true,
"esModuleInterop": true,

Side notes:

• Typescript 2.9.0 has a bug with this JSON feature, it was fixed with 2.9.2
• The esModuleInterop is only necessary for the default import of the colorsJson. If you leave it set to false then you have to import it with import * as colorsJson from '../colors.json'