External module "utils/async/compose/docs/types/index.d"

Export assignment composeAsync

• composeAsync(f0: BinaryFunction, f1: VariadicFunction, ...f: Array<VariadicFunction>): CompositeFunction

• Function composition.

  Notes

  • Returns a composite function. Starting from the right, the composite function evaluates each function and passes the result as the first argument of the next function. The result of the leftmost function is the result of the whole.

  Parameters

  • f0: BinaryFunction

    first function to compose

  • f1: VariadicFunction

    second function to compose

  • Rest ...f: Array<VariadicFunction>

    remaining functions to compose

  Returns CompositeFunction

  composite function

  Example

  function a( x, next ) {
      setTimeout( onTimeout, 0 );
      function onTimeout() {
          next( null, 2*x );
      }
  }
  
  function b( x, next ) {
      setTimeout( onTimeout, 0 );
      function onTimeout() {
          next( null, x+3 );
      }
  }
  
  function c( x, next ) {
      setTimeout( onTimeout, 0 );
      function onTimeout() {
          next( null, x/5 );
      }
  }
  
  var f = composeAsync( c, b, a );
  
  function done( error, result ) {
      if ( error ) {
          throw error;
      }
      console.log( result );
      // => 3
  }
  
  f( 6, done );