#no-did-mount-set-state

#Configuration

import { defineConfig, reactPlugin } from '@rslint/core';

export default defineConfig([
  reactPlugin.configs.recommended,
  {
    rules: {
      'react/no-did-mount-set-state': 'error',
    },
  },
]);

Disallow this.setState inside componentDidMount.

Updating the state immediately after the initial mount triggers a second render() call and can lead to property/layout thrashing.

#Rule Details

This rule flags any this.setState call whose enclosing class method, class field initializer, or object-literal property is keyed componentDidMount. By default, calls inside a nested function (regular or arrow) are allowed — enable disallow-in-func to forbid them too.

Examples of incorrect code for this rule:

var Hello = createReactClass({
  componentDidMount: function () {
    this.setState({
      name: this.props.name.toUpperCase(),
    });
  },
});

class Hello extends React.Component {
  componentDidMount() {
    this.setState({
      name: this.props.name.toUpperCase(),
    });
  }
}

Examples of correct code for this rule:

var Hello = createReactClass({
  componentDidMount: function () {
    someNonMemberFunction(arg);
    this.someHandler = this.setState;
  },
});

var Hello = createReactClass({
  componentDidMount: function () {
    someClass.onSomeEvent(function (data) {
      this.setState({
        data: data,
      });
    });
  },
});

#Rule Options

{ "react/no-did-mount-set-state": ["error", "disallow-in-func"] }

With disallow-in-func set, the rule also flags this.setState calls inside nested functions:

var Hello = createReactClass({
  componentDidMount: function () {
    someClass.onSomeEvent(function (data) {
      this.setState({
        data: data,
      });
    });
  },
});

#React Version

The rule is a no-op when settings.react.version is explicitly set to >= 16.3.0, matching eslint-plugin-react's shouldBeNoop gate for componentDidMount.

#Differences from ESLint

• Pre-release version strings such as "16.3.0-rc.1" are treated as 16.3.0 (rule becomes a no-op). eslint-plugin-react follows semver, where 16.3.0-rc.1 ranks below 16.3.0, so it keeps the rule active. If you pin a pre-release version and want the rule to flag this.setState inside componentDidMount, set settings.react.version to a release version such as "16.2.0".

#Original Documentation

• eslint-plugin-react / no-did-mount-set-state