The yin to asMutable's yang. Because it applies to mutable collections,
this operation is mutable and returns itself. Once performed, the mutable
copy has become immutable and can be safely returned from a function.
Another way to avoid creation of intermediate Immutable maps is to create
a mutable copy of this collection. Mutable copies always return this,
and thus shouldn't be used for equality. Your function should never return
a mutable copy of a collection, only use it internally to create a new
collection. If possible, use withMutations as it provides an easier to
use API.
Note: if the collection is already mutable, asMutable returns itself.
Note: Not all methods can be used on a mutable collection or within
withMutations! Only set and merge may be used mutatively.
Returns a new Map containing no keys or values.
Returns a new Map which excludes this key.
Note: delete cannot be safely used in IE8, but is provided to mirror
the ES6 collection API.
Returns a new Map having removed the value at this keyPath. If any keys
in keyPath do not exist, no change will occur.
Returns a new Map resulting from merging the provided Iterables (or JS objects) into this Map. In other words, this takes each entry of each iterable and sets it on this Map.
If any of the values provided to merge are not Iterable (would return
false for Immutable.Iterable.isIterable) then they are deeply converted
via Immutable.fromJS before being merged. However, if the value is an
Iterable but includes non-iterable JS objects or arrays, those nested
values will be preserved.
var x = Immutable.Map({a: 10, b: 20, c: 30});
var y = Immutable.Map({b: 40, a: 50, d: 60});
x.merge(y) // { a: 50, b: 40, c: 30, d: 60 }
y.merge(x) // { b: 20, a: 10, d: 60, c: 30 }Like merge(), but when two Iterables conflict, it merges them as well,
recursing deeply through the nested data.
var x = Immutable.fromJS({a: { x: 10, y: 10 }, b: { x: 20, y: 50 } });
var y = Immutable.fromJS({a: { x: 2 }, b: { y: 5 }, c: { z: 3 } });
x.mergeDeep(y) // {a: { x: 2, y: 10 }, b: { x: 20, y: 5 }, c: { z: 3 } }A combination of updateIn and mergeDeep, returning a new Map, but
performing the deep merge at a point arrived at by following the keyPath.
In other words, these two lines are equivalent:
x.updateIn(['a', 'b', 'c'], abc => abc.mergeDeep(y));
x.mergeDeepIn(['a', 'b', 'c'], y);Like mergeDeep(), but when two non-Iterables conflict, it uses the
merger function to determine the resulting value.
var x = Immutable.fromJS({a: { x: 10, y: 10 }, b: { x: 20, y: 50 } });
var y = Immutable.fromJS({a: { x: 2 }, b: { y: 5 }, c: { z: 3 } });
x.mergeDeepWith((prev, next) => prev / next, y)
// {a: { x: 5, y: 10 }, b: { x: 20, y: 10 }, c: { z: 3 } }A combination of updateIn and merge, returning a new Map, but
performing the merge at a point arrived at by following the keyPath.
In other words, these two lines are equivalent:
x.updateIn(['a', 'b', 'c'], abc => abc.merge(y));
x.mergeIn(['a', 'b', 'c'], y);Like merge(), mergeWith() returns a new Map resulting from merging
the provided Iterables (or JS objects) into this Map, but uses the
merger function for dealing with conflicts.
var x = Immutable.Map({a: 10, b: 20, c: 30});
var y = Immutable.Map({b: 40, a: 50, d: 60});
x.mergeWith((prev, next) => prev / next, y) // { a: 0.2, b: 0.5, c: 30, d: 60 }
y.mergeWith((prev, next) => prev / next, x) // { b: 2, a: 5, d: 60, c: 30 }Returns a new Map also containing the new key, value pair. If an equivalent key already exists in this Map, it will be replaced.
Returns a new Map having set value at this keyPath. If any keys in
keyPath do not exist, a new immutable Map will be created at that key.
Returns a new Map having updated the value at this key with the return
value of calling updater with the existing value, or notSetValue if
the key was not set. If called with only a single argument, updater is
called with the Map itself.
Equivalent to: map.set(key, updater(map.get(key, notSetValue))).
Returns a new Map having applied the updater to the entry found at the
keyPath.
If any keys in keyPath do not exist, new Immutable Maps will
be created at those keys. If the keyPath does not already contain a
value, the updater function will be called with notSetValue, if
provided, otherwise undefined.
var data = Immutable.fromJS({ a: { b: { c: 10 } } });
data = data.updateIn(['a', 'b', 'c'], val => val * 2);
// { a: { b: { c: 20 } } }If the updater function returns the same value it was called with, then
no change will occur. This is still true if notSetValue is provided.
var data1 = Immutable.fromJS({ a: { b: { c: 10 } } });
data2 = data1.updateIn(['x', 'y', 'z'], 100, val => val);
assert(data2 === data1);Every time you call one of the above functions, a new immutable Map is created. If a pure function calls a number of these to produce a final return value, then a penalty on performance and memory has been paid by creating all of the intermediate immutable Maps.
If you need to apply a series of mutations to produce a new immutable
Map, withMutations() creates a temporary mutable copy of the Map which
can apply mutations in a highly performant manner. In fact, this is
exactly how complex mutations like merge are done.
As an example, this results in the creation of 2, not 4, new Maps:
var map1 = Immutable.Map();
var map2 = map1.withMutations(map => {
map.set('a', 1).set('b', 2).set('c', 3);
});
assert(map1.size === 0);
assert(map2.size === 3);Note: Not all methods can be used on a mutable collection or within
withMutations! Only set and merge may be used mutatively.
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Represents an immutable data structure