在 Angular 7 项目中导入 JSON

Question

In my Angular project I'm importing JSON files for my own little localization service. I'm usingthe method suggested here , updating my typings.d.ts to

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

This worked fine for Angular 6, but after the update to Angular 7 my imports seem to be undefined when I try to access a property.

import * as de from './strings/de.json';
import * as en from './strings/en.json';

var s = en["mykey"]

The JSON has a very simple key => value structure:

{
  "myKey": "My Headline",
  …
}

What has changed between 6.1 & 7 that could lead to this behaviour?

Answer 1

Turns out with Angular 7 & TypeScript 3.1 there actually have been some changes (I guess they have been there since TS 2.9+?). Using the code in the question, all values are wrapped inside a 'default'-object. To prevent this I had to simplify the import statements:

import de from './strings/de.json';
import en from './strings/en.json';

Also see this question for more details on how to import JSON files in TypeScript.

Answer 2

After a lot of digging and trail and error, I finally got my app to import JSON correctly in Angular 7:

1. Firstly, remove

   "resolveJsonModule": true "esModuleInterop": true

   from tsconfig.json , if you have that in there from other non-Angular 7 specific answers.

2. Create src/typings.d.ts :

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

3. Update typeRoots in tsconfig.json to use src/typings.d.ts , eg:

    "typeRoots": [ "node_modules/@types", "src/typings.d.ts" ],

4. Import JSON:

    import data from './data.json'; console.log(data);

Answer 3

In Angular 7 I had to take these steps:

(1) imports

import pkg from '../../package.json'

(2) tsconfig.json

{
  "compilerOptions": {
    "allowSyntheticDefaultImports": true,
    "esModuleInterop": true,
    "resolveJsonModule": true,
    AND more compiler options here
  }
}

(3) angular.json (to stop ng lint breaking on JSON imports)

The only change here is to add ... "**/*.json"

"lint": {
  "builder": "@angular-devkit/build-angular:tslint",
  "options": {
    "tsConfig": [
      "src/tsconfig.app.json",
      "src/tsconfig.spec.json"
    ],
    "exclude": [
      "**/node_modules/**",
      "**/*.json"
    ]
  }
}

Answer 4

I was looking for a solution that would work without me tinkering with the angular.json file

I solved it by exporting my JSON as a .ts constant:

export const TEST_DATA = {...};

and then import it to my components