57 lines
1.4 KiB
Markdown
57 lines
1.4 KiB
Markdown
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# Prefer using `.each` rather than manual loops (`prefer-each`)
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<!-- end auto-generated rule header -->
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Reports where you might be able to use `.each` instead of native loops.
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## Rule details
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This rule triggers a warning if you use test case functions like `describe`,
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`test`, and `it`, in a native loop - generally you should be able to use `.each`
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instead which gives better output and makes it easier to run specific cases.
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Examples of **incorrect** code for this rule:
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```js
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for (const number of getNumbers()) {
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it('is greater than five', function () {
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expect(number).toBeGreaterThan(5);
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});
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}
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for (const [input, expected] of data) {
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beforeEach(() => setupSomething(input));
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test(`results in ${expected}`, () => {
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expect(doSomething()).toBe(expected);
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});
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}
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```
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Examples of **correct** code for this rule:
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```js
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it.each(getNumbers())(
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'only returns numbers that are greater than seven',
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number => {
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expect(number).toBeGreaterThan(7);
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},
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);
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describe.each(data)('when input is %s', ([input, expected]) => {
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beforeEach(() => setupSomething(input));
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test(`results in ${expected}`, () => {
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expect(doSomething()).toBe(expected);
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});
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});
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// we don't warn on loops _in_ test functions because those typically involve
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// complex setup that is better done in the test function itself
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it('returns numbers that are greater than five', () => {
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for (const number of getNumbers()) {
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expect(number).toBeGreaterThan(5);
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}
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});
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```
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