Benchmark.js documentation

`Benchmark`

`Benchmark(name, fn [, options={}])`

The Benchmark constructor.

Note: The Benchmark constructor exposes a handful of lodash methods to make working with arrays, collections, and objects easier. The lodash methods are:
each/forEach, forOwn, has, indexOf, map, and reduce

Arguments

name (string): A name to identify the benchmark.
fn (Function|string): The test to benchmark.
[options={}] (Object): Options object.

Example

// basic usage (the `new` operator is optional)
var bench = new Benchmark(fn);// or using a name first
var bench = new Benchmark('foo', fn);
// or with options
var bench = new Benchmark('foo', fn, {
  // displayed by `Benchmark#toString` if `name` is not available
  'id': 'xyz',
  // called when the benchmark starts running
  'onStart': onStart,
  // called after each run cycle
  'onCycle': onCycle,
  // called when aborted
  'onAbort': onAbort,
  // called when a test errors
  'onError': onError,
  // called when reset
  'onReset': onReset,
  // called when the benchmark completes running
  'onComplete': onComplete,
  // compiled/called before the test loop
  'setup': setup,
  // compiled/called after the test loop
  'teardown': teardown
});
// or name and options
var bench = new Benchmark('foo', {
  // a flag to indicate the benchmark is deferred
  'defer': true,
  // benchmark test function
  'fn': function(deferred) {
    // call `Deferred#resolve` when the deferred test is finished
    deferred.resolve();
  }
});
// or options only
var bench = new Benchmark({
  // benchmark name
  'name': 'foo',
  // benchmark test as a string
  'fn': '[1,2,3,4].sort()'
});
// a test’s `this` binding is set to the benchmark instance
var bench = new Benchmark('foo', function() {
  'My name is '.concat(this.name); // "My name is foo"
});

`Benchmark.version`

# Ⓢ Ⓣ

(string): The semantic version number.

`Benchmark.filter(array, callback)`

# Ⓢ Ⓣ

A generic Array#filter like method.

Arguments

array (Array): The array to iterate over.
callback (Function|string): The function/alias called per iteration.

Returns

(Array): A new array of values that passed callback filter.

Example

// get odd numbers
Benchmark.filter([1, 2, 3, 4, 5], function(n) {
  return n % 2;
}); // -> [1, 3, 5];// get fastest benchmarks
Benchmark.filter(benches, 'fastest');
// get slowest benchmarks
Benchmark.filter(benches, 'slowest');
// get benchmarks that completed without erroring
Benchmark.filter(benches, 'successful');

`Benchmark.formatNumber(number)`

# Ⓢ Ⓣ

Converts a number to a more readable comma-separated string representation.

Arguments

number (number): The number to convert.

Returns

(string): The more readable string representation.

`Benchmark.invoke(benches, name [, args])`

# Ⓢ Ⓣ

Invokes a method on all items in an array.

Arguments

benches (Array): Array of benchmarks to iterate over.
name (Object|string): The name of the method to invoke OR options object.
[args] (…)*: Arguments to invoke the method with.

Returns

(Array): A new array of values returned from each method invoked.

Example

// invoke `reset` on all benchmarks
Benchmark.invoke(benches, 'reset');// invoke `emit` with arguments
Benchmark.invoke(benches, 'emit', 'complete', listener);
// invoke `run(true)`, treat benchmarks as a queue, and register invoke callbacks
Benchmark.invoke(benches, {
  // invoke the `run` method
  'name': 'run',
  // pass a single argument
  'args': true,
  // treat as queue, removing benchmarks from front of `benches` until empty
  'queued': true,
  // called before any benchmarks have been invoked.
  'onStart': onStart,
  // called between invoking benchmarks
  'onCycle': onCycle,
  // called after all benchmarks have been invoked.
  'onComplete': onComplete
});

`Benchmark.join(object [, separator1=',', separator2=': '])`

# Ⓢ Ⓣ

Creates a string of joined array values or object key-value pairs.

Arguments

object (Array|Object): The object to operate on.
[separator1=','] (string): The separator used between key-value pairs.
[separator2=': '] (string): The separator used between keys and values.

Returns

(string): The joined result.

`Benchmark.runInContext([context=root])`

# Ⓢ Ⓣ

Create a new Benchmark function using the given context object.

Arguments

[context=root] (Object): The context object.

Returns

(Function): Returns a new Benchmark function.

`Benchmark.prototype`

`Benchmark.prototype.aborted`

# Ⓢ Ⓣ

(boolean): A flag to indicate if the benchmark is aborted.

`Benchmark.prototype.compiled`

# Ⓢ Ⓣ

(Function, string): The compiled test function.

`Benchmark.prototype.count`

# Ⓢ Ⓣ

(number): The number of times a test was executed.

`Benchmark.prototype.cycles`

# Ⓢ Ⓣ

(number): The number of cycles performed while benchmarking.

`Benchmark.prototype.error`

# Ⓢ Ⓣ

(Object): The error object if the test failed.

`Benchmark.prototype.fn`

# Ⓢ Ⓣ

(Function, string): The test to benchmark.

`Benchmark.prototype.hz`

# Ⓢ Ⓣ

(number): The number of executions per second.

`Benchmark.prototype.running`

# Ⓢ Ⓣ

(boolean): A flag to indicate if the benchmark is running.

`Benchmark.prototype.setup`

# Ⓢ Ⓣ

(Function, string): Compiled into the test and executed immediately before the test loop.

Example

// basic usage
var bench = Benchmark({
  'setup': function() {
    var c = this.count,
        element = document.getElementById('container');
    while (c--) {
      element.appendChild(document.createElement('div'));
    }
  },
  'fn': function() {
    element.removeChild(element.lastChild);
  }
});// compiles to something like:
var c = this.count,
    element = document.getElementById('container');
while (c--) {
  element.appendChild(document.createElement('div'));
}
var start = new Date;
while (count--) {
  element.removeChild(element.lastChild);
}
var end = new Date - start;
// or using strings
var bench = Benchmark({
  'setup': '\
    var a = 0;\n\
    (function() {\n\
      (function() {\n\
        (function() {',
  'fn': 'a += 1;',
  'teardown': '\
         }())\n\
       }())\n\
     }())'
});
// compiles to something like:
var a = 0;
(function() {
  (function() {
    (function() {
      var start = new Date;
      while (count--) {
        a += 1;
      }
      var end = new Date - start;
    }())
  }())
}())

`Benchmark.prototype.teardown`

# Ⓢ Ⓣ

(Function, string): Compiled into the test and executed immediately after the test loop.

`Benchmark.prototype.abort()`

# Ⓢ Ⓣ

Aborts the benchmark without recording times.

Returns

(Object): The benchmark instance.

`Benchmark.prototype.clone(options)`

# Ⓢ Ⓣ

Creates a new benchmark using the same test and options.

Arguments

options (Object): Options object to overwrite cloned options.

Returns

(Object): The new benchmark instance.

Example

var bizarro = bench.clone({
  'name': 'doppelganger'
});

`Benchmark.prototype.compare(other)`

# Ⓢ Ⓣ

Determines if a benchmark is faster than another.

Arguments

other (Object): The benchmark to compare.

Returns

(number): Returns -1 if slower, 1 if faster, and 0 if indeterminate.

`Benchmark.Suite.prototype.emit(type [, args])`

# Ⓢ Ⓣ

Executes all registered listeners of the specified event type.

Arguments

type (Object|string): The event type or object.
[args] (…)*: Arguments to invoke the listener with.

Returns

()*: Returns the return value of the last listener executed.

`Benchmark.Suite.prototype.listeners(type)`

# Ⓢ Ⓣ

Returns an array of event listeners for a given type that can be manipulated to add or remove listeners.

Arguments

type (string): The event type.

Returns

(Array): The listeners array.

`Benchmark.Suite.prototype.off([type, listener])`

# Ⓢ Ⓣ

Unregisters a listener for the specified event type(s), or unregisters all listeners for the specified event type(s), or unregisters all listeners for all event types.

Arguments

[type] (string): The event type.
[listener] (Function): The function to unregister.

Returns

(Object): The benchmark instance.

Example

// unregister a listener for an event type
bench.off('cycle', listener);// unregister a listener for multiple event types
bench.off('start cycle', listener);
// unregister all listeners for an event type
bench.off('cycle');
// unregister all listeners for multiple event types
bench.off('start cycle complete');
// unregister all listeners for all event types
bench.off();

`Benchmark.Suite.prototype.on(type, listener)`

# Ⓢ Ⓣ

Registers a listener for the specified event type(s).

Arguments

type (string): The event type.
listener (Function): The function to register.

Returns

(Object): The benchmark instance.

Example

// register a listener for an event type
bench.on('cycle', listener);// register a listener for multiple event types
bench.on('start cycle', listener);

`Benchmark.prototype.reset()`

# Ⓢ Ⓣ

Reset properties and abort if running.

Returns

(Object): The benchmark instance.

`Benchmark.prototype.run([options={}])`

# Ⓢ Ⓣ

Runs the benchmark.

Arguments

[options={}] (Object): Options object.

Returns

(Object): The benchmark instance.

Example

// basic usage
bench.run();// or with options
bench.run({ 'async': true });

`Benchmark.prototype.toString()`

# Ⓢ Ⓣ

Displays relevant benchmark information when coerced to a string.

Returns

(string): A string representation of the benchmark instance.

`Benchmark.options`

# Ⓢ Ⓣ

(Object): The default options copied by benchmark instances.

`Benchmark.options.async`

# Ⓢ Ⓣ

(boolean): A flag to indicate that benchmark cycles will execute asynchronously by default.

`Benchmark.options.defer`

# Ⓢ Ⓣ

(boolean): A flag to indicate that the benchmark clock is deferred.

`Benchmark.options.delay`

# Ⓢ Ⓣ

(number): The delay between test cycles (secs).

`Benchmark.options.id`

# Ⓢ Ⓣ

(string): Displayed by Benchmark#toString when a name is not available (auto-generated if absent).

`Benchmark.options.initCount`

# Ⓢ Ⓣ

(number): The default number of times to execute a test on a benchmark’s first cycle.

`Benchmark.options.maxTime`

# Ⓢ Ⓣ

(number): The maximum time a benchmark is allowed to run before finishing (secs).

Note: Cycle delays aren't counted toward the maximum time.

`Benchmark.options.minSamples`

# Ⓢ Ⓣ

(number): The minimum sample size required to perform statistical analysis.

`Benchmark.options.minTime`

# Ⓢ Ⓣ

(number): The time needed to reduce the percent uncertainty of measurement to 1% (secs).

`Benchmark.options.name`

# Ⓢ Ⓣ

(string): The name of the benchmark.

`Benchmark.options.onAbort`

# Ⓢ Ⓣ

An event listener called when the benchmark is aborted.

`Benchmark.options.onComplete`

# Ⓢ Ⓣ

An event listener called when the benchmark completes running.

`Benchmark.options.onCycle`

# Ⓢ Ⓣ

An event listener called after each run cycle.

`Benchmark.options.onError`

# Ⓢ Ⓣ

An event listener called when a test errors.

`Benchmark.options.onReset`

# Ⓢ Ⓣ

An event listener called when the benchmark is reset.

`Benchmark.options.onStart`

# Ⓢ Ⓣ

An event listener called when the benchmark starts running.

`Benchmark.platform`

# Ⓢ Ⓣ

(Object): Platform object with properties describing things like browser name, version, and operating system. See platform.js.

`Benchmark.support`

# Ⓢ Ⓣ

(Object): An object used to flag environments/features.

`Benchmark.support.browser`

# Ⓢ Ⓣ

(boolean): Detect if running in a browser environment.

`Benchmark.support.decompilation`

# Ⓢ Ⓣ

(boolean): Detect if function decompilation is support.

`Benchmark.support.timeout`

# Ⓢ Ⓣ

(boolean): Detect if the Timers API exists.

`Benchmark.prototype.stats`

# Ⓢ Ⓣ

(Object): An object of stats including mean, margin or error, and standard deviation.

`Benchmark.prototype.stats.deviation`

# Ⓢ Ⓣ

(number): The sample standard deviation.

`Benchmark.prototype.stats.mean`

# Ⓢ Ⓣ

(number): The sample arithmetic mean (secs).

`Benchmark.prototype.stats.moe`

# Ⓢ Ⓣ

(number): The margin of error.

`Benchmark.prototype.stats.rme`

# Ⓢ Ⓣ

(number): The relative margin of error (expressed as a percentage of the mean).

`Benchmark.prototype.stats.sample`

# Ⓢ Ⓣ

(Array): The array of sampled periods.

`Benchmark.prototype.stats.sem`

# Ⓢ Ⓣ

(number): The standard error of the mean.

`Benchmark.prototype.stats.variance`

# Ⓢ Ⓣ

(number): The sample variance.

`Benchmark.prototype.times`

# Ⓢ Ⓣ

(Object): An object of timing data including cycle, elapsed, period, start, and stop.

`Benchmark.prototype.times.cycle`

# Ⓢ Ⓣ

(number): The time taken to complete the last cycle (secs).

`Benchmark.prototype.times.elapsed`

# Ⓢ Ⓣ

(number): The time taken to complete the benchmark (secs).

`Benchmark.prototype.times.period`

# Ⓢ Ⓣ

(number): The time taken to execute the test once (secs).

`Benchmark.prototype.times.timeStamp`

# Ⓢ Ⓣ

(number): A timestamp of when the benchmark started (ms).

`Benchmark.Deferred`

`Benchmark.Deferred(clone)`

# Ⓢ Ⓣ

The Deferred constructor.

Arguments

clone (Object): The cloned benchmark instance.

`Benchmark.Deferred.prototype`

`Benchmark.Deferred.prototype.benchmark`

# Ⓢ Ⓣ

(Object): The deferred benchmark instance.

`Benchmark.Deferred.prototype.cycles`

# Ⓢ Ⓣ

(number): The number of deferred cycles performed while benchmarking.

`Benchmark.Deferred.prototype.elapsed`

# Ⓢ Ⓣ

(number): The time taken to complete the deferred benchmark (secs).

`Benchmark.Deferred.prototype.timeStamp`

# Ⓢ Ⓣ

(number): A timestamp of when the deferred benchmark started (ms).

`Benchmark.Event`

`Benchmark.Event(type)`

# Ⓢ Ⓣ

The Event constructor.

Arguments

type (Object|string): The event type.

`Benchmark.Event.prototype`

`Benchmark.Event.prototype.aborted`

# Ⓢ Ⓣ

(boolean): A flag to indicate if the emitters listener iteration is aborted.

`Benchmark.Event.prototype.cancelled`

# Ⓢ Ⓣ

(boolean): A flag to indicate if the default action is cancelled.

`Benchmark.Event.prototype.currentTarget`

# Ⓢ Ⓣ

(Object): The object whose listeners are currently being processed.

`Benchmark.Event.prototype.result`

# Ⓢ Ⓣ

(Mixed): The return value of the last executed listener.

`Benchmark.Event.prototype.target`

# Ⓢ Ⓣ

(Object): The object to which the event was originally emitted.

`Benchmark.Event.prototype.timeStamp`

# Ⓢ Ⓣ

(number): A timestamp of when the event was created (ms).

`Benchmark.Event.prototype.type`

# Ⓢ Ⓣ

(string): The event type.

`Benchmark.Suite`

`Benchmark.Suite(name [, options={}])`

# Ⓢ Ⓣ

The Suite constructor.

Note: Each Suite instance has a handful of wrapped lodash methods to make working with Suites easier. The wrapped lodash methods are:
each/forEach, indexOf, map, and reduce

Arguments

name (string): A name to identify the suite.
[options={}] (Object): Options object.

Example

// basic usage (the `new` operator is optional)
var suite = new Benchmark.Suite;// or using a name first
var suite = new Benchmark.Suite('foo');
// or with options
var suite = new Benchmark.Suite('foo', {
  // called when the suite starts running
  'onStart': onStart,
  // called between running benchmarks
  'onCycle': onCycle,
  // called when aborted
  'onAbort': onAbort,
  // called when a test errors
  'onError': onError,
  // called when reset
  'onReset': onReset,
  // called when the suite completes running
  'onComplete': onComplete
});

`Benchmark.Suite.prototype`

`Benchmark.Suite.prototype.aborted`

# Ⓢ Ⓣ

(boolean): A flag to indicate if the suite is aborted.

`Benchmark.Suite.prototype.length`

# Ⓢ Ⓣ

(number): The number of benchmarks in the suite.

`Benchmark.Suite.prototype.running`

# Ⓢ Ⓣ

(boolean): A flag to indicate if the suite is running.

`Benchmark.Suite.prototype.abort()`

# Ⓢ Ⓣ

Aborts all benchmarks in the suite.

Returns

(Object): The suite instance.

`Benchmark.Suite.prototype.add(name, fn [, options={}])`

# Ⓢ Ⓣ

Adds a test to the benchmark suite.

Arguments

name (string): A name to identify the benchmark.
fn (Function|string): The test to benchmark.
[options={}] (Object): Options object.

Returns

(Object): The benchmark instance.

Example

// basic usage
suite.add(fn);// or using a name first
suite.add('foo', fn);
// or with options
suite.add('foo', fn, {
  'onCycle': onCycle,
  'onComplete': onComplete
});
// or name and options
suite.add('foo', {
  'fn': fn,
  'onCycle': onCycle,
  'onComplete': onComplete
});
// or options only
suite.add({
  'name': 'foo',
  'fn': fn,
  'onCycle': onCycle,
  'onComplete': onComplete
});

`Benchmark.Suite.prototype.clone(options)`

# Ⓢ Ⓣ

Creates a new suite with cloned benchmarks.

Arguments

options (Object): Options object to overwrite cloned options.

Returns

(Object): The new suite instance.

`Benchmark.Suite.prototype.emit(type [, args])`

# Ⓢ Ⓣ

Executes all registered listeners of the specified event type.

Arguments

type (Object|string): The event type or object.
[args] (…)*: Arguments to invoke the listener with.

Returns

()*: Returns the return value of the last listener executed.

`Benchmark.Suite.prototype.filter(callback)`

# Ⓢ Ⓣ

An Array#filter like method.

Arguments

callback (Function|string): The function/alias called per iteration.

Returns

(Object): A new suite of benchmarks that passed callback filter.

`Benchmark.Suite.prototype.listeners(type)`

# Ⓢ Ⓣ

Returns an array of event listeners for a given type that can be manipulated to add or remove listeners.

Arguments

type (string): The event type.

Returns

(Array): The listeners array.

`Benchmark.Suite.prototype.off([type, listener])`

# Ⓢ Ⓣ

Unregisters a listener for the specified event type(s), or unregisters all listeners for the specified event type(s), or unregisters all listeners for all event types.

Arguments

[type] (string): The event type.
[listener] (Function): The function to unregister.

Returns

(Object): The benchmark instance.

Example

// unregister a listener for an event type
bench.off('cycle', listener);// unregister a listener for multiple event types
bench.off('start cycle', listener);
// unregister all listeners for an event type
bench.off('cycle');
// unregister all listeners for multiple event types
bench.off('start cycle complete');
// unregister all listeners for all event types
bench.off();

`Benchmark.Suite.prototype.on(type, listener)`

# Ⓢ Ⓣ

Registers a listener for the specified event type(s).

Arguments

type (string): The event type.
listener (Function): The function to register.

Returns

(Object): The benchmark instance.

Example

// register a listener for an event type
bench.on('cycle', listener);// register a listener for multiple event types
bench.on('start cycle', listener);

`Benchmark.Suite.prototype.reset()`

# Ⓢ Ⓣ

Resets all benchmarks in the suite.

Returns

(Object): The suite instance.

`Benchmark.Suite.prototype.run([options={}])`

# Ⓢ Ⓣ

Runs the suite.

Arguments

[options={}] (Object): Options object.

Returns

(Object): The suite instance.

Example

// basic usage
suite.run();// or with options
suite.run({ 'async': true, 'queued': true });

`Benchmark.Suite.options`

# Ⓢ Ⓣ

(Object): The default options copied by suite instances.

`Benchmark.Suite.options.name`

# Ⓢ Ⓣ

(string): The name of the suite.