Can't do a default import in Angular 9

Question

I changed tsconfig.json by adding this properties

"esModuleInterop": true, "allowSyntheticDefaultImports": true,

in order to be able to import a npm package import * as ms from "ms";

But I still get this error

This module is declared with using 'export =', and can only be used with a default import when using the 'allowSyntheticDefaultImports' flag.

What am I missing?

Update:

If I change with import ms from "ms", then it works fine with the compiler but not with VSCode linter and the error is

 can only be default-imported using the 'allowSyntheticDefaultImports' flagts(1259)
index.d.ts(25, 1): This module is declared with using 'export =', and can only be used with a default import when using the 'allowSyntheticDefaultImports' flag.

As I said now is working but VSCode have a problem.

Solution 1

The problem is how the package declared the export, you can still import using the default import:

import ms from "ms";

Solution 2

You can just do something like this

import * as printJS from 'print-js'

Solution 3

"allowSyntheticDefaultImports": true

This flag solved problem, but it should be added to compilerOptions section of tsconfig.json

Solution 4

If you have this error trying to import localforage into angular 9, I used this (Angular 9.1.12, Typescript 3.9.6):

npm install localforage

// tsconfig.json

{
  "compileOnSave": false,
  "compilerOptions": {
    "baseUrl": "./",
    "outDir": "./dist/out-tsc",
    "sourceMap": true,
    "declaration": false,
    "downlevelIteration": true,
    "experimentalDecorators": true,
    "module": "esnext",
    "moduleResolution": "node",
    "importHelpers": true,
    "target": "es2015",
    "lib": [
      "es2018",
      "dom"
    ]
  },
  "angularCompilerOptions": {
    "fullTemplateTypeCheck": true,
    "strictInjectionParameters": true,
    "esModuleInterop": true, <----------------------------add this
    "allowSyntheticDefaultImports": true <----------------------------and this
  },
}

// any component or service

import * as localforage from 'localforage';

constructor() {
    localforage.setItem('localforage', 'localforage value');
    setTimeout(() => {
      localforage.getItem('localforage').then((e) => {
       console.log(e);
      });
    }, 5000);
    setTimeout( async () => {
      const RES = await localforage.getItem('localforage');
      console.log('RES', RES);
    }, 10000);
  }

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