Value which implements iterable protocol
Confirms if given object is an iterable and is not a string (unless allowString
option is passed)
const isIterable = require("type/iterable/is");
isIterable([]); // true
isIterable({}); // false
isIterable("foo"); // false
isIterable("foo", { allowString: true }); // true
Supports also denyEmpty
option
isIterable([], { denyEmpty: true }); // false
isIterable(["foo"], { denyEmpty: true }); // true
If given argument is an iterable, it is returned back. Otherwise TypeError
is thrown.
By default string primitives are rejected unless allowString
option is passed.
const ensureIterable = require("type/iterable/ensure");
ensureIterable([]); // []
ensureIterable("foo", { allowString: true }); // "foo"
ensureIterable({}); // Thrown TypeError: null is not expected iterable
Pass denyEmpty
option to require non empty iterables
ensureIterable([], { denyEmpty: true }); // Thrown TypeError: [] is not expected iterable
Items can be validated by passing ensureItem
option. Note that in this case:
- A newly created instance of array with coerced values is returned
- Error message lists up to three invalid items
const ensureString = require("type/string/ensure");
ensureIterable(new Set(["foo", 12]), { ensureItem: ensureString }); // ["foo", "12"]
/*
Below invocation with crash with:
TypeError: [object Set] is not expected iterable value.
Following items are invalid:
- [object Object]
*/
ensureIterable(new Set(["foo", {}]), { ensureItem: ensureString });