Devtools-fps NPM

devtools-fps

Validator

devtools-fps is an FPS monitor for web application performance observability without the use of browser devtools.

Why? 🙃

In order to monitor FPS without other processes running at the same time (browser devtools), but also while application is rendered at full screen. devtools-fps allows you to interact with it by pausing "recording" and inspecting a snapshot of a buffer for a specific frame performance and time the frame was rendered at.

Install

yarn

yarn add -D devtools-fps

npm

npm install -D devtools-fps

Usage

Anywhere in your code (preferably in the file main.ts) import devtools-fps:

import devtoolsFPS from "devtools-fps";

...this will automatically start at the bottom-right corner of application page at 220x50 size.

Run your app! You'll see the devtools-fps display running on top of your content.

Positioning

You can drag devtools-fps display around your screen, it will automatically snap to page edges.

Resizing

Grab the control points of devtools-fps display, which will activate when you hover close to it, then drag it around to give it any size you like.

Inspect

Click on devtools-fps to toggle inspect mode. If inspect mode is activated, the rendering will pause and a Tooltip will be displayed with data related to the corresponding buffer data, which includes:

FPS
Timestamp HH:MM:SS:MS (in local time)

Use it to reference various app events at specific times. Much like performance devtools in chrome.

Configuration

You can further configure devtools-fps by using .config() method to customize it`s appearance, size, position and buffer size:

// config type
type config = {
  /** display width in px */
  width?: number;
  /** display height in px */
  height?: number;
  /** buffer size will determine the resolution and speed of motion */
  bufferSize?: number;
  /** CSS style of canvas. You shouldn't set "width", "height" and "position" */
  style?: Omit<Partial<CSSStyleDeclaration>, "width" | "height" | "position">;
};

Example:

import  devtoolsFPS  from 'devtools-fps';
// configure defaults
devtoolsFPS.config({
    width: 220
    height: 74,
    bufferSize: 110,
    style: {
        backgroundColor: `rgba(0,0,50,0.3)`,
        top: '0px',
        left: '0px',
        boxShadow: "5px 5px 10px 0 rgba(0,0,0,0.5)",
        opacity: '0.5',
        // etc...
    }
})

// rest of your app

In cases where your IDE will remove unused imports, simply call .config() with empty parameters:

import devtoolsFPS from "devtools-fps";
devtoolsFPS.config(); // <-- like this

Buffer

Buffer size will determine the resolutions of the FPS timeline, the bigger the size the higher the resolution and therefor the slower the timeline will appear to shift. Conversely, smaller buffer size will enlarge individual FSP timeline slices, which means it will appear to shift faster.