lib.md

JS-Profiler

Library

// 1. Import the library
const jsProfiler = require('js-profiler');

// 2. Configure js-profiler
const options = {
  json: true,
  precision: 2,
  unit: 'µs'
};

// 3. Run the profiler
jsProfiler.run(options)
  .then((report) => {
    console.log(JSON.stringify(report, null, 2));
  });

The js-profiler module exports an object providing two functions:

list(verbosity) => Array<object>

Returns an array of available profiles. Each profile is represented by a name and description.

Parameters

verbosity int

default: 1

The verbosity to use for profile description output.

Use the constants provided in verbosity.

run(options) => Promise

Calling run() starts profile execution and returns a Promise which resolves with the profiling results.

Parameters

options object

The library provides analogous options to the CLI.

console boolean

default: false

If set to true, a ConsoleReporter is attached, writing profile results to the console.

iterations int

default: 1000

Specify the number of iterations per profiled function.

json boolean

default: false

If set to true, a JSONReporter is attached, writing profile results to the console in JSON format.

magnitude int

default: 1000

Specify the magnitude of test data, i.e. the number of items to supply to each profiled function.

memory boolean

default: false

If set to true, memory consumption is measured and reported.

ATTENTION: Enabling memory reporting significantly slows down profile execution.

precision object

default: { time: 4, memory: 4 }

Specify the number of decimal places to output for results.

profiles Array<string>

default: undefined

If specified, only profiles with the names provided are executed.

jsperformance.run({
  profiles: [
    'recursion',
    'loops'
  ]
}).then((report) => {
  console.log(report);
});

units object

default: { time: 'auto', memory: 'auto' }

Specify the unit to use for time output. Possible values are:

• auto: Automatically convert between units where appropriate.
• ms or milliseconds: Milliseconds
• µs or microseconds: Microseconds
• B: Byte
• KB: Kilobyte
• MB: Megabyte

Use the constants found in units.

verbosity int

default: 1

Set output verbosity. Possible values are:

• 0 Quiet. Output only results
• 1 Normal. Output name, description and result of profiled functions.
• 2 Verbose. Output verbose data.

Use the constants found in verbosity;