sivakumar-kailasam / eslint-plugin-react-intl

An eslint plugin to enforce react-intl translations and formatting in web apps.

@calm/eslint-plugin-react-intl

This is a plugin to ensure that Intl translations are being made correctly with react-intl. Since they should be stored in an object for translation, this disables plain text between html tags.

The plugin is actively supported by the Calm engineering team, and contributions/concerns are welcome at https://github.com/calm/eslint-plugin-react-intl.

There are three options to enable, and we recommend enabling all of them to ensure proper translations in all languages.

The { noTrailingWhitespace: true } option is set by default and is not necessary to declare in the rules section. This is recommended as some languages don't have spaces between words. Additionally, the option ignoreLinks is set to true by default. Depending on your use case, you may want to disable this.

Use Cases

Formatted Message validation

• Checks to make sure plain text doesn't exist within html tags (should be translated)
• <a> tags by default are not checked (this can be disabled)
• Numbers are ignored (they're the same in every language)
• Trailing whitespace is not allowed (this can be disabled)
• Non-alphanumeric values are ignored (such as -)
• Can enable enforcing label, aria-label attributes being translated (<track label="subtitles" />)
• Can enable enforcing alt attributes being translated (<img alt="description" />)
• Can enable enforcing inputProps being translated (<Checkbox value="checkedA" inputProps={{ 'aria-label': 'Checkbox A' }} />)
  • This is specific to some React libraries, such as MaterialUI
  • Example can be seen here: https://material-ui.com/components/checkboxes/#accessibility

Missing Values validation

• In defaultMessage attributes within components, {variable} declarations must be declared in the values attribute
• It will look over anything before a comma, allowing for FormatJS plurals
  • Ex. defaultMessage="{number} {number, plural, one {Day} other {Days}}" will resolve 1 variable as number

Missing Attribute validation

• components must have both defaultMessage and id attributes set
  • Calm chooses to always require these, but you can optionally disable defaultMessage with option requireDefaultMessage : false
• defaultMessage and id attributes cannot be empty
• Spread operator by default is not allowed
  • Spread operator can't be evaluated by eslint's AST, so translations can't be guaranteed
• requireDescription can optionally be set to require that all translations contain the description attribute
• Use the formatDefineMessages: true option in order to also check the defineMessages declaration from react-intl
  • BE CAREFUL - This assumes that defineMessages will always mean the react-intl method, so do not declare other defineMessages functions unless they maintain the same formatting as react-intl
• Optional requireIdAsString: false will allow for variables in the id field
  • BE CAREFUL - variables in id fields can result in duplicate strings being translated, as well as the possibility of a changed variable leading to an id without a translation associated with it

Installation

You'll first need to install ESLint:

$ npm i eslint --save-dev

Next, install @calm/eslint-plugin-react-intl:

$ npm install @calm/eslint-plugin-react-intl --save-dev

Note: If you installed ESLint globally (using the -g flag) then you must also install @calm/eslint-plugin-react-intl globally.

Usage

Add @calm/react-intl to the plugins section of your .eslintrc configuration file. You can omit the eslint-plugin- prefix:

{
    "plugins": [
        "@calm/react-intl"
    ]
}

Then configure the rules you want to use under the rules section. It's recommended that you explicitly set each option.
The rules (with their default settings) are listed below.

{
    "rules": {
        "@calm/react-intl/missing-formatted-message": [2,
          {
            "noTrailingWhitespace": true,
            "ignoreLinks": true,
            "enforceLabels": false,
            "enforceImageAlts": false,
            "enforceInputProps": false
          }
        ],
        "@calm/react-intl/missing-attribute": [2,
            {
                "noTrailingWhitespace": true,
                "noSpreadOperator": true,
                "requireDescription": false,
                "formatDefineMessages": false,
                "requireIdAsString": true,
                "requireDefaultMessage": true,
            }
        ],
        "@calm/react-intl/missing-values": 2
    }
}

Supported Rules

• missing-formatted-message
• missing-attribute
• missing-values