Enforces return statements in callbacks of array's methods (array-callback-return) #859

feross · 2017-04-13T02:29:07Z

ESLint just promoted this rule to their 'eslint:recommended' rule set, so it's probably pretty reliable. I want to check how much of the ecosystem this effects and consider enabling it.

Array has several methods for filtering, mapping, and folding. If we forget to write return statement in a callback of those, it's probably a mistake.

This rule enforces usage of return statement in callbacks of array's methods.

This rule finds callback functions of the following methods, then checks usage of return statement.

Array.from
Array.prototype.every
Array.prototype.filter
Array.prototype.find
Array.prototype.findIndex
Array.prototype.map
Array.prototype.reduce
Array.prototype.reduceRight
Array.prototype.some
Array.prototype.sort

https://github.com/eslint/eslint/blob/master/docs/rules/array-callback-return.md

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dcousens · 2017-04-13T05:51:06Z

Yes.

dcousens · 2017-04-13T05:51:42Z

~~Though, I have used .some in the past to short-circuit a forEach loop~~

feross · 2017-04-13T21:03:58Z

@dcousens It's fine to use .some in that way. You're still using return in the function callback right?

dcousens · 2017-04-14T06:22:27Z

If we forget to write return statement in a callback of those, it's probably a mistake.

I misread it as if we forget to write return statement for those, indeed, you are right 👍

feross · 2020-10-28T19:49:02Z

About 7% ecosystem effect:

1..207
# tests 207
# pass  193
# fail  14

Examples of failures that I think are good errors to report:

    const tuples = this.stringTuples().filter((tuple) => {
      if (tuple[0] === protocols.names.ipfs.code) {
        return true
      }
    })

  tuples.map(tup => {
    const proto = protoFromTuple(tup)
    parts.push(proto.name)
    if (tup.length > 1) {
      parts.push(tup[1])
    }
  })

More marginal cases where more explicitness doesn't hurt:

    keys.some(function (key, i) {
      tasks[key](function (err, result) { each(key, err, result) })
      if (i === limit - 1) return true // early return
    })

    input.some(item => {
      if (typeof item === 'string') {
        opts.name = corePath.basename(item)
        return true
      } else if (!item.unknownName) {
        opts.name = item.path[item.path.length - 1]
        return true
      }
    })

for: #859

feross added the enhancement label Apr 13, 2017

feross added the accepted label Oct 28, 2020

feross added this to the standard 16 milestone Oct 28, 2020

feross closed this as completed in standard/eslint-config-standard@6979424 Oct 29, 2020

feross added the ecosystem impact label Oct 29, 2020

feross added a commit that referenced this issue Oct 29, 2020

changelog

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for: #859

github-actions bot locked as resolved and limited conversation to collaborators Oct 30, 2021

mightyiam added this to The Standard Project Sep 16, 2023

mightyiam moved this to Done in The Standard Project Sep 16, 2023

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Enforces return statements in callbacks of array's methods (array-callback-return) #859

Enforces return statements in callbacks of array's methods (array-callback-return) #859

feross commented Apr 13, 2017 •

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dcousens commented Apr 13, 2017

dcousens commented Apr 13, 2017 •

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feross commented Apr 13, 2017

dcousens commented Apr 14, 2017 •

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feross commented Oct 28, 2020

Enforces return statements in callbacks of array's methods (array-callback-return) #859

Enforces return statements in callbacks of array's methods (array-callback-return) #859

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feross commented Apr 13, 2017 • edited Loading

dcousens commented Apr 13, 2017

dcousens commented Apr 13, 2017 • edited Loading

feross commented Apr 13, 2017

dcousens commented Apr 14, 2017 • edited Loading

feross commented Oct 28, 2020

feross commented Apr 13, 2017 •

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dcousens commented Apr 13, 2017 •

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dcousens commented Apr 14, 2017 •

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