Closed Bug 1217077 Opened 5 years ago Closed 5 years ago

Remove use of for-each from services/.

Categories

(Firefox :: General, defect)

defect
Not set
normal

Tracking

()

RESOLVED FIXED
Firefox 45
Tracking Status
firefox45 --- fixed

People

(Reporter: arai, Assigned: arai)

References

Details

Attachments

(2 files)

Need to replace non-standard for-each with one of:
  * for-of
  * for-in
  * array.map/array.filter for array-comprehension
as a part of bug 1083470.

converting rules are following:
  * for-each
    * for each (let x in array) { ... }
      -> for (let x of array) { ... }
    * for each (let x in object) { ... }
      -> for (let key in object) { let x = object[key]; ... }
    * for each (let [key, value] in Iterator(object)) { ... }
      -> for (let key in object) { let value = object[key]; ... }
    * for each (let x in array) { ... }
      where array can be null or undefined
      -> if (array) { for (let x of array) { ... } }

  * legacy array comprehension with for-each
    * [EXPR for each (x in array)]
      -> array.map(x => EXPR)
    * [EXPR for each (x in array) if (COND)]
      -> array.filter(x => COND).map(x => EXPR)
    * [x for each (x in array) if (COND)]
      -> array.filter(x => COND)
    * [EXPR for each ([i, x] in Iterator(array)) if (g(x, i)]
      -> array.filter((x, i) => g(x, i)).map((x => EXPR)
    * [EXPR for each (x in arraylike)]
      -> Array.from(arraylike).map(x => EXPR)
    * [EXPR for each (x in string)]
      -> Array.prototype.slice.call(string).map(x => EXPR)
         // Array.from behaves differently for surrogate-pair

I'll post a patch shortly.
here's the result of investigation for some complicated case.
update from other bugs.

Newer Array comprehension ([for (x of y) x]) is now also non-standard and we shouldn't use it as a replacement for legacy array comprehension.  I used map/filter instead in the patch :)
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Array_comprehensions
Attachment #8676978 - Flags: review?(gps) → review+
https://hg.mozilla.org/mozilla-central/rev/1de5ecadccee
Status: NEW → RESOLVED
Closed: 5 years ago
Resolution: --- → FIXED
Target Milestone: --- → Firefox 45
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