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.map()

Creates a new Minified list from the current list using the given callback function.
Util module only.

Syntax Variants

list.map(mapFunc)
list.map(mapFunc, ctx)
_.map(list, mapFunc)
_.map(list, mapFunc, ctx)

Parameters

list
a list to transform. Can be an array, a Minified list or any other array-like structure with length property.
mapFunc
The callback function(item, index) to invoke for each item:
item
The current list element.
index
The second the zero-based index of the current element.
this
The given context if not null. Otherwise the list.
(callback return value)
This value will replace the original value in the new list.
ctx (optional)
a context to pass to the callback as 'this'.
(return value)
the new list

Description

Creates a new Minified list from the current list using the given callback function. The callback is invoked once for each element of the current list. The callback results will be added to the result list.

map() is a simpler version of collect(). Unlike collect(), it always creates lists of the same size as the input list, but it is easier to use if the resulting list should contain nulls or nested list.

Example

Goes through a list of numbers and creates a new list with each value increased by 1: 

var inced = _(3, 7, 11, 5, 19, 3).map(function(number, index) {
    return number + 1;
});

Example

The previous example with a native array is input. Note that the result is always a Minified list: 

var inced = _.map([3, 7, 11, 5, 19, 3], function(number, index) {
    return number + 1;
});

See also..

  • collect() is a more powerful version of map().

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Functions