External module "utils/inmap/docs/types/index.d"

Export assignment inmap

• inmap<T, U>(collection: Collection<T>, fcn: Callback<T, U>, thisArg?: ThisParameterType<Callback<T, U>>): Collection<T>

• Invokes a function once for each element in a collection and updates the collection in-place.

  Notes

  • The invoked function's return value is cached prior to updating a collection. Before updating the collection, a collection must be inspected to ensure that a collection has not been resized during invocation such that an index no longer has a corresponding element in the collection. Were a return value automatically used to update a collection, an input collection could be converted into a sparse data structure. While some might consider this a feature, here, we take stance that a user should be less clever.

  Type parameters

  • T

  • U

  Parameters

  • collection: Collection<T>

    input collection

  • fcn: Callback<T, U>

    function to invoke

  • Optional thisArg: ThisParameterType<Callback<T, U>>

    execution context

  Returns Collection < T >

  input collection

  Example

  function scale( value, index, collection ) {
      return value * index;
  }
  
  var arr = [ 1, 2, 3, 4 ];
  
  var out = inmap( arr, scale );
  // returns [ 0, 2, 6, 12 ]
  
  var bool = ( out === arr );
  // returns true