Usage

var funseqAsync = require( '@stdlib/utils-async-function-sequence' );

funseqAsync( ...fcn )

Returns a pipeline function. Starting from the left, the pipeline function evaluates each function and passes the result as the first argument to the next function. The result of the rightmost function is the result of the whole.

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 = funseqAsync( a, b, c );

function done( error, result ) {
    if ( error ) {
        throw error;
    }
    console.log( result );
    // => 3
}

f( 6, done ); // ((2*x)+3)/5

The last argument provided to each function is a next callback which accepts two arguments:

• error: error argument
• result: function result

Only the leftmost function is explicitly permitted to accept multiple arguments. All other functions are evaluated as binary functions.

function a( x, y, next ) {
    setTimeout( onTimeout, 0 );
    function onTimeout() {
        next( null, (x*5) + (y*3) );
    }
}

function b( r, next ) {
    setTimeout( onTimeout, 0 );
    function onTimeout() {
        next( null, r+12 );
    }
}

var f = funseqAsync( a, b );

function done( error, result ) {
    if ( error ) {
        throw error;
    }
    console.log( result );
    // => 50
}

f( 4, 6, done );