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Fix the custom matcher example

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jbranchaud
2020-01-28 12:29:14 -06:00
parent ea4092b769
commit f61df4b73c
1 changed files with 8 additions and 3 deletions
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11
javascript/define-a-custom-jest-matcher.md
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@@ -18,12 +18,14 @@ expect.extend({
if (pass) {
return {
pass: true,
message: `Actual ${recieved.id} matches expected ${expected.id}`
message: () =>
`expected id:${expected.id} to not match actual id:${recieved.id}`
};
} else {
return {
pass: false,
message: `Actual ${recieved.id} does not match expected ${expected.id}`
message: () =>
`expected id:${expected.id} to match actual id:${recieved.id}`
};
}
}
@@ -32,14 +34,17 @@ expect.extend({
This defines the name of the matcher (`toHaveMatchingId`), contains some logic
to figure out whether `received` and `expected` pass the matcher, and then two
return conditions (`pass: true` and `pass: false`) with accompanying messages.
return conditions (`pass: true` and `pass: false`) with accompanying
message-returning functions.
It can then be used like any other Jest matcher:
```javascript
test("compare objects", () => {
expect({ id: "001" }).toHaveMatchingId({ id: "001" });
// ✅
expect({ id: "001" }).toHaveMatchingId({ id: "002" });
// ❌ expected id:002 to match actual id:001
});
```