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I keep on finding that Array functions are missing in GAS, eg calling find gives the error: Cannot find function find in object

The only docs I can find on this are somewhat ambiguous: https://developers.google.com/apps-script/guides/services/#basic_javascript_features

Apps Script is based on JavaScript 1.6, plus a few features from 1.7 and 1.8. Many basic JavaScript features are thus available in addition to the built-in and advanced Google services: you can use common objects like Array, Date, RegExp, and so forth, as well as the Math and Object global objects. However, because Apps Script code runs on Google's servers (not client-side, except for HTML-service pages), browser-based features like DOM manipulation or the Window API are not available.

How can I see what exact methods are available on Array?

Rubén
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robd
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3 Answers3

24

Logger.log(Object.getOwnPropertyNames(Array.prototype)) gives the following, which I think it is the correct list:

[constructor, toString, toLocaleString, toSource, join, reverse, sort, push, pop, shift, unshift, splice, concat, slice, indexOf, lastIndexOf, every, filter, forEach, map, some, reduce, reduceRight, length]

robd
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14

When in Doubt, Test Yourself!

Check it out for yourself with:

function es_feature_test(f) {
  var a = [1, 2, 3, 4];

  try {
    a[f].call(a, function () { return true; });
    Logger.log("+ %s", f);
  } catch (e) {
    Logger.log("- %s", f);
  }
}

function es_test() {
  [
    "any",
    "every",
    "fill",
    "filter",
    "find",
    "findIndex",
    "forEach",
    "includes",
    "indexOf",
    "join",
    "keys",
    "lastIndexOf",
    "map",
    "pop",
    "push",
    "reduce",
    "reduceRight",
    "reverse",
    "shift",
    "slice",
    "some",
    "sort",
    "splice"
  ].forEach(function (fName) {
    es_feature_test(fName);
  });
}

Note: this function list is not exhaustive and is only for example purposes.

Which outputs something like:

[16-09-05 14:48:38:843 CEST] - any
[16-09-05 14:48:38:843 CEST] + every
[16-09-05 14:48:38:844 CEST] - fill
[16-09-05 14:48:38:844 CEST] + filter
[16-09-05 14:48:38:845 CEST] - find
[16-09-05 14:48:38:846 CEST] - findIndex
[16-09-05 14:48:38:846 CEST] + forEach
[16-09-05 14:48:38:847 CEST] - includes
[16-09-05 14:48:38:847 CEST] + indexOf
[16-09-05 14:48:38:848 CEST] + join
[16-09-05 14:48:38:848 CEST] - keys
[16-09-05 14:48:38:849 CEST] + lastIndexOf
[16-09-05 14:48:38:849 CEST] + map
[16-09-05 14:48:38:850 CEST] + pop
[16-09-05 14:48:38:850 CEST] + push
[16-09-05 14:48:38:851 CEST] + reduce
[16-09-05 14:48:38:851 CEST] + reduceRight
[16-09-05 14:48:38:851 CEST] + reverse
[16-09-05 14:48:38:852 CEST] + shift
[16-09-05 14:48:38:852 CEST] + slice
[16-09-05 14:48:38:853 CEST] + some
[16-09-05 14:48:38:853 CEST] + sort
[16-09-05 14:48:38:854 CEST] + splice

Alternatively, robd's method works fine too, except it only tells you the list of methods that are visible. It doesn't tell you:

  • whether they actually work (they could block on access),
  • which methods are not visible.

So I prefer my slightly more explicit approach.

An even better method than mine would be to actually check function test cases to make sure behaviors are correct, but... oh well...

GAS Function Call Support Fun Fact

Here's something weird: I first tested using an implementation with .apply() instead of .call() (out of habit), and strangely enough only the methods supported in the GAS editor appeared as supported. Works fine using .call() though. Rather odd.

I Want my Functional Tools Back!

Check out underscoreGS.

haylem
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    Google has added almost all of those now. As of now the only one in that list not supported is the function call: `any`. I ran your sweet code and it outputs plus in front of all of them except for that function call. Output: `May 3, 2020, 9:57:11 AM Info - any` – Magne May 03 '20 at 08:00
  • @Magne: Thanks for the update! That's good to know, haven't used GAS in a while myself, but it's a handy tool. – haylem May 04 '20 at 10:03
2

Besides robd's answer there is also the 2d arrays library.
According to the picture (but not the documentation) that one has a find function

Robin Gertenbach
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  • There's also the [UnderscoreGS](https://sites.google.com/site/scriptsexamples/custom-methods/underscoregs) library. – haylem Sep 05 '16 at 12:54
  • See also https://mathjs.org for working with 2D arrays, also known as Matrices. – Magne May 03 '20 at 08:02