time-to-botec

repl.txt (6828B)

---

 
 {{alias}}( collection, [options,] indicator, done )
     Groups values according to an indicator function.
 
     When invoked, the indicator function is provided a maximum of four
     arguments:
 
     - `value`: collection value
     - `index`: collection index
     - `collection`: the input collection
     - `next`: a callback to be invoked after processing a collection `value`
 
     The actual number of provided arguments depends on function length. If the
     indicator function accepts two arguments, the indicator function is
     provided:
 
     - `value`
     - `next`
 
     If the indicator function accepts three arguments, the indicator function is
     provided:
 
     - `value`
     - `index`
     - `next`
 
     For every other indicator function signature, the indicator function is
     provided all four arguments.
 
     The `next` callback takes two arguments:
 
     - `error`: error argument
     - `group`: value group
 
     If an indicator function calls the `next` callback with a truthy `error`
     argument, the function suspends execution and immediately calls the `done`
     callback for subsequent `error` handling.
 
     If provided an empty collection, the function calls the `done` callback with
     an empty object as the second argument.
 
     The `group` returned by an indicator function should be a value which can be
     serialized as an object key.
 
     Execution is *not* guaranteed to be asynchronous. To guarantee asynchrony,
     wrap the `done` callback in a function which either executes at the end of
     the current stack (e.g., `nextTick`) or during a subsequent turn of the
     event loop (e.g., `setImmediate`, `setTimeout`).
 
     The function does not support dynamic collection resizing.
 
     The function does not skip `undefined` elements.
 
     Parameters
     ----------
     collection: Array|TypedArray|Object
         Input collection over which to iterate. If provided an object, the
         object must be array-like (excluding strings and functions).
 
     options: Object (optional)
         Function options.
 
     options.limit: integer (optional)
         Maximum number of pending invocations. Default: Infinity.
 
     options.series: boolean (optional)
         Boolean indicating whether to process each collection element
         sequentially. Default: false.
 
     options.returns: string (optional)
         If `values`, values are returned; if `indices`, indices are returned; if
         `*`, both indices and values are returned. Default: 'values'.
 
     options.thisArg: any (optional)
         Execution context.
 
     indicator: Function
         Indicator function specifying which group an element in the input
         collection belongs to.
 
     done: Function
         A callback invoked either upon processing all collection elements or
         upon encountering an error.
 
     Examples
     --------
     // Basic usage:
     > function indicator( value, index, next ) {
     ...     setTimeout( onTimeout, value );
     ...     function onTimeout() {
     ...         console.log( value );
     ...         next( null, ( index%2 === 0 ) );
     ...     }
     ... };
     > function done( error, result ) {
     ...     if ( error ) {
     ...         throw error;
     ...     }
     ...     console.log( result );
     ... };
     > var arr = [ 3000, 2500, 1000 ];
     > {{alias}}( arr, indicator, done )
     1000
     2500
     3000
     { "true": [ 1000, 3000 ], "false": [ 2500 ] }
 
     // Output group results as indices:
     > var opts = { 'returns': 'indices' };
     > {{alias}}( arr, opts, indicator, done )
     1000
     2500
     3000
     { "true": [ 2, 0 ], "false": [ 1 ] }
 
     // Output group results as index-value pairs:
     > opts = { 'returns': '*' };
     > {{alias}}( arr, opts, indicator, done )
     1000
     2500
     3000
     { "true": [ [ 2, 1000 ], [ 0, 3000 ] ], "false": [ [ 1, 2500 ] ] }
 
     // Limit number of concurrent invocations:
     > function indicator( value, index, next ) {
     ...     setTimeout( onTimeout, value );
     ...     function onTimeout() {
     ...         console.log( value );
     ...         next( null, ( index%2 === 0 ) );
     ...     }
     ... };
     > function done( error, result ) {
     ...     if ( error ) {
     ...         throw error;
     ...     }
     ...     console.log( result );
     ... };
     > var opts = { 'limit': 2 };
     > var arr = [ 3000, 2500, 1000 ];
     > {{alias}}( arr, opts, indicator, done )
     2500
     3000
     1000
     { "true": [ 3000, 1000 ], "false": [ 2500 ] }
 
     // Process sequentially:
     > function indicator( value, index, next ) {
     ...     setTimeout( onTimeout, value );
     ...     function onTimeout() {
     ...         console.log( value );
     ...         next( null, ( index%2 === 0 ) );
     ...     }
     ... };
     > function done( error, result ) {
     ...     if ( error ) {
     ...         throw error;
     ...     }
     ...     console.log( result );
     ... };
     > var opts = { 'series': true };
     > var arr = [ 3000, 2500, 1000 ];
     > {{alias}}( arr, opts, indicator, done )
     3000
     2500
     1000
     { "true": [ 3000, 1000 ], "false": [ 2500 ] }
 
 
 {{alias}}.factory( [options,] indicator )
     Returns a function which groups values according to an indicator function.
 
     Parameters
     ----------
     options: Object (optional)
         Function options.
 
     options.limit: integer (optional)
         Maximum number of pending invocations. Default: Infinity.
 
     options.series: boolean (optional)
         Boolean indicating whether to process each collection element
         sequentially. Default: false.
 
     options.returns: string (optional)
         If `values`, values are returned; if `indices`, indices are returned; if
         `*`, both indices and values are returned. Default: 'values'.
 
     options.thisArg: any (optional)
         Execution context.
 
     indicator: Function
         Indicator function specifying which group an element in the input
         collection belongs to.
 
     Returns
     -------
     out: Function
         A group-by function.
 
     Examples
     --------
     > function indicator( value, index, next ) {
     ...     setTimeout( onTimeout, value );
     ...     function onTimeout() {
     ...         console.log( value );
     ...         next( null, ( index%2 === 0 ) );
     ...     }
     ... };
     > var opts = { 'series': true };
     > var f = {{alias}}.factory( opts, indicator );
     > function done( error, result ) {
     ...     if ( error ) {
     ...         throw error;
     ...     }
     ...     console.log( result );
     ... };
     > var arr = [ 3000, 2500, 1000 ];
     > f( arr, done )
     3000
     2500
     1000
     { "true": [ 3000, 1000 ], "false": [ 2500 ] }
     > arr = [ 2000, 1500, 1000 ];
     > f( arr, done )
     2000
     1500
     1000
     { "true": [ 2000, 1000 ], "false": [ 1500 ] }
 
     See Also
     --------