CODEWITHSUNDEEP
jestjsspfx
user11092881
user11092881

Reputation:

Cannot find a declared module when running a Jest unit test

I am trying to test a spfx webpart component and I am getting the following error:

Test suite failed to run

    Cannot find module 'WebPartContentStrings' from 'WebContentContainer.tsx'

I did some digging and I found that inside my component I do the following:

import * as strings from "WebPartContentStrings";

And I have this file:

declare module 'WebPartContentStrings' {
  const strings: IWebPartContentStrings;
  export = strings;
}

However, it seems when I mock the component Jest cannot interpret the import instruction correctly and cannot find the module even though the application can find it when I host it on a server. Is there a way to import the strings in a different way for Jest?

Upvotes: 1

Views: 1340

Answers (2)

Georgi Kolev
Georgi Kolev

Reputation: 1

Instead of doing

import * as strings from "WebPartContentStrings";

pass the strings of your webpart as props to the component and use those the way you use normal props. For example:

Props interface definition:

export interface IYourComponentsProps { strings: IWebPartContentStrings }

Using some of the strings in your react component's render function:

<p>{this.props.strings.exampleString}</p>

This will fix the import issue you're facing.

Cheers.

Upvotes: 0

yunusunver
yunusunver

Reputation: 590

I had the same problem.It has to be fixed when 'react' the 'jsx' property in tsconfig.json.

For example:

{
  "compilerOptions": {
    "target": "esnext",
    "module": "esnext",
    "moduleResolution": "node",
    "jsx": "react",
    "types": ["jest", "node"],
    "lib": [
      "dom",
      "dom.iterable",
      "esnext"
    ],
    "strict": true,
    "noEmit": true,
    "allowJs": true,
    "skipLibCheck": true,
    "esModuleInterop": true,
    "isolatedModules": true,
    "resolveJsonModule": true
  },
  "exclude": [
    "node_modules"
  ],
  "include": [
    "next-env.d.ts",
    "**/*.ts",
    "**/*.tsx"
  ]
}

Upvotes: 1

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