no-missing-placeholders.md

Disallow missing placeholders in rule report messages (eslint-plugin/no-missing-placeholders)

💼 This rule is enabled in the ✅ recommended config.

Report messages in rules can have placeholders surrounded by curly brackets.

context.report({
  node,
  message: '{{disallowedNode}} nodes are not allowed.',
  data: { disallowedNode: node.type },
});

// Resulting message: e.g. 'IfStatement nodes are not allowed.'

However, if no data argument is provided, or no matching replacement key exists in the data argument, the raw curly brackets will end up in the report message. This is usually a mistake.

Rule Details

This rule aims to disallow missing placeholders in rule report messages.

Examples of incorrect code for this rule:

/* eslint eslint-plugin/no-missing-placeholders: error*/

module.exports = {
  create(context) {
    context.report({
      node,
      message: '{{something}} is wrong.',
    });

    context.report({
      node,
      message: '{{something}} is wrong.',
      data: { somethingElse: 'foo' },
    });

    context.report(node, '{{something}} is wrong.', { somethingElse: 'foo' });
  },
};

Examples of correct code for this rule:

/* eslint eslint-plugin/no-missing-placeholders: error*/

module.exports = {
  create(context) {
    context.report({
      node,
      message: 'something is wrong.',
    });

    context.report({
      node,
      message: '{{something}} is wrong.',
      data: { something: 'foo' },
    });

    context.report(node, '{{something}} is wrong.', { something: 'foo' });
  },
};

When Not To Use It

If you want to use rule messages that actually contain double-curly bracket text, you should turn off this rule.

Further Reading

• ESLint rule docs: Using Message Placeholders