react/jsx-no-bind

A .bind() call, an arrow function or a function expression in a prop creates a new function on every render. The child sees a prop that changed, so React.memo and PureComponent can't skip its render, and an effect that depends on the function runs again.

The rule also follows a prop back to a const or a function declared inside the component.

Configure#

Off by default. To turn it on:

bunfig.toml

[lint.rules]
"react/jsx-no-bind" = "error" # or "warn"

Every option, set to its default:

bunfig.toml

[lint.rules]
"react/jsx-no-bind" = ["error", {
  allowArrowFunctions = false,
  allowFunctions = false,
  allowBind = false,
  ignoreRefs = false,
  ignoreDOMComponents = false,
}]

Examples#

example.jsx3 problems

function Toolbar({ onSave, doc }) {
  const handleReset = () => doc.reset();

  return (
    <div>
      <Button onClick={() => onSave(doc)} />
      <Button onClick={doc.print.bind(doc)} />
      <Button onClick={handleReset} />
    </div>
  );
}

example.jsxNo problems

function Toolbar({ onSave, doc }) {
  const handleSave = useCallback(() => onSave(doc), [onSave, doc]);

  return <Button onClick={handleSave} />;
}

Options#

Option	Default	What it does
`allowArrowFunctions`	`false`	Allow arrow functions.
`allowFunctions`	`false`	Allow `function` expressions and declarations.
`allowBind`	`false`	Allow `.bind()`.
`ignoreRefs`	`false`	Don't check the `ref` prop.
`ignoreDOMComponents`	`false`	Don't check DOM elements such as `<button>`. They're never memoized, so a new function costs them nothing.

With ignoreDOMComponents, components are still checked:

example.jsxwith { "ignoreDOMComponents": true }No problems

const button = <button onClick={() => save(doc)}>Save</button>;

example.jsxwith { "ignoreDOMComponents": true }1 problem

const button = <Button onClick={() => save(doc)}>Save</Button>;

When not to use it#

A new function only costs something if the child is memoized or uses the function as a dependency. In most other code an inline arrow function is fine and easier to read. The React Compiler also memoizes these functions for you.