Can only call expect.extend(..) once as it overwrites the proxy's custom extend #72

sb3700 · 2024-01-30T22:40:17Z

Bug

package version: v1.1.3
node version: 14.21.3
npm (or yarn) version: 6.14.18
jest version: 26.6.2

Relevant code or config

expect.extend({
  toBe1(received) {
    const pass = received === 1;
    return pass
      ? { pass, message: () => `expected ${received} to be 1` }
      : { pass, message: () => `expected ${received} not to be 1` };
  }
});

expect.extend({
  toBe2(received) {
    const pass = received === 2;
    return pass
      ? { pass, message: () => `expected ${received} to be 2` }
      : { pass, message: () => `expected ${received} not to be 2` };
  }
});

console.log(expect['toBe1'], expect['toBe2']);
// [Function (anonymous)] undefined

What happened (please provide anything you think will help):
Thanks for the library!

The problem is at https://github.com/mattphillips/jest-expect-message/blob/main/src/withMessage.js#L92.

expectProxy = Object.assign(expectProxy, expect); overwrites expectProxy.extend with expect.extend.

It could be fixed by changing the line to:

for (const key of expect) {
  if (key !== 'extend') {    // or !(key in eventProxy)
    expectProxy[key] = expect[key];
  }
}

The text was updated successfully, but these errors were encountered:

seggewiss · 2024-07-17T06:47:16Z

Actually expect is not iterable but this would work:

expectProxy.extend = o => {
    expect.extend(o); // add new matchers to expect

    Object.keys(expect).forEach((key) => {
        if (key !== 'extend') {    // or !(key in eventProxy)
            expectProxy[key] = expect[key];
        }
    })
};

I used patch packages locally but will open a MR here hopefully it will be merged 😊

seggewiss linked a pull request Jul 17, 2024 that will close this issue

Fix expect extend #73

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Can only call expect.extend(..) once as it overwrites the proxy's custom extend #72

Can only call expect.extend(..) once as it overwrites the proxy's custom extend #72

sb3700 commented Jan 30, 2024

seggewiss commented Jul 17, 2024 •

edited

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Can only call expect.extend(..) once as it overwrites the proxy's custom extend #72

Can only call expect.extend(..) once as it overwrites the proxy's custom extend #72

Comments

sb3700 commented Jan 30, 2024

seggewiss commented Jul 17, 2024 • edited Loading

seggewiss commented Jul 17, 2024 •

edited

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