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Detect CSS Reflows

Detect CSS Reflows (detect-css-reflows)

Let the developers know if changes to a specific CSS property will trigger changes on the Layout, Composite or Paint rendering pipeline.

Why is this important?

Understanding what rendering pipeline operations will be triggered by changes on specific CSS properties can prevent users from introducing unintentional performance hits.

What does the hint check?

It scans the css properties against a defined properties and associated rendering triggers.

Examples that trigger the hint

A list of code examples that will fail this hint. It’s good to put some edge cases in here.

Examples that pass the hint

In the following example, this hint will warn user that making changes to the padding-left property will trigger changes on the Layout and Paint pipeline.

.example {
    padding-left: auto;

Can the hint be configured?

You can decide the granularity and severity of your reports up to the following categories:

  • detect-css-reflows/composite
  • detect-css-reflows/layout
  • detect-css-reflows/paint

How to use this hint?

To use it you will have to install it via npm:

npm install hint --save-dev

Note: You can make npm install it as a devDependency using the --save-dev parameter, or to install it globally, you can use the -g parameter. For other options see npm‘s documentation.

And then activate it via the .hintrc configuration file:

    "connector": {...},
    "formatters": [...],
    "parsers": [...],
    "hints": {
        "detect-css-reflows/composite": "off",
        "detect-css-reflows/layout": "hint",
        "detect-css-reflows/paint": "off"

Further Reading