iterate-value
Iterate any iterable JS value. Works robustly in all environments, all versions.
In modern engines, [...value] or
Array.from(value) or
for (const item of value) { } are sufficient to iterate an
iterable value (an object with a Symbol.iterator method).
However, older engines: - may lack Symbol, array spread, or
for..of support altogether - may have
Symbol.iterator but not implement it on everything it
should, like arguments objects - may have Map and
Set, but a non-standard name for the iterator-producing
method (.iterator or ['@@iterator'], eg) and
no syntax to support it - may be old versions of Firefox that produce
values until they throw a StopIteration exception, rather than having
iteration result objects - may be polyfilled/shimmed/shammed, with
es6-shim or core-js or similar
This library attempts to provide an abstraction over all that complexity!
If called with a single value, it will return an array of the yielded values. If also called with a callback function, it will instead call that callback once for each yielded value.
In node v13+, exports is used by the
es-get-iterator dependency to provide a lean implementation
that lacks all the complexity described above, in combination with the
browser field so that bundlers will pick up the proper
implementation.
If you are targeting browsers that definitely all have Symbol
support, then you can configure your bundler to replace
require('has-symbols')() with a literal true,
which should allow dead code elimination to reduce the size of the
bundled code.
Example
var iterate = require('iterate-value');
var assert = require('assert');
assert.deepEqual(iterate('a 💩'), ['a', ' ', '💩']);
assert.deepEqual(iterate([1, 2]), [1, 2]);
assert.deepEqual(iterate(new Set([1, 2])), [1, 2]);
assert.deepEqual(iterate(new Map([[1, 2], [3, 4]])), [[1, 2], [3, 4]]);
function assertWithCallback(iterable, expected) {
var values = [];
var callback = function (x) { values.push(x); };
iterate(iterable, callback);
assert.deepEqual(values, expected);
}
assertWithCallback('a 💩', ['a', ' ', '💩']);
assertWithCallback([1, 2], [1, 2]);
assertWithCallback(new Set([1, 2]), [1, 2]);
assertWithCallback(new Map([[1, 2], [3, 4]]), [[1, 2], [3, 4]]);Tests
Simply clone the repo, npm install, and run
npm test