Rule: trailing-comma

Requires or disallows trailing commas in array and object literals, destructuring assignments, function typings, named imports and exports and function parameters.

Notes:

Config

One argument which is an object with the keys multiline and singleline. Both can be set to a string ("always" or "never") or an object.

The object can contain any of the following keys: "arrays", "objects", "functions", "imports", "exports", and "typeLiterals"; each key can have one of the following values: "always", "never", and "ignore". Any missing keys will default to "ignore".

• "multiline" checks multi-line object literals.
• "singleline" checks single-line object literals.

An array is considered “multiline” if its closing bracket is on a line after the last array element. The same general logic is followed for object literals, function typings, named import statements and function parameters.

To align this rule with the ECMAScript specification that is implemented in modern JavaScript VMs, there is a third option esSpecCompliant. Set this option to true to disallow trailing comma on object and array rest and rest parameters.

Config examples

"trailing-comma": [true, {"multiline": "always", "singleline": "never"}]

"trailing-comma": [
  true,
  {
    "multiline": {
      "objects": "always",
      "arrays": "always",
      "functions": "never",
      "typeLiterals": "ignore"
    },
    "esSpecCompliant": true
  }
]

Schema

{
  "type": "object",
  "properties": {
    "multiline": {
      "anyOf": [
        {
          "type": "string",
          "enum": [
            "always",
            "never"
          ]
        },
        {
          "type": "object",
          "properties": {
            "arrays": {
              "type": "string",
              "enum": [
                "always",
                "never",
                "ignore"
              ]
            },
            "exports": {
              "type": "string",
              "enum": [
                "always",
                "never",
                "ignore"
              ]
            },
            "functions": {
              "type": "string",
              "enum": [
                "always",
                "never",
                "ignore"
              ]
            },
            "imports": {
              "type": "string",
              "enum": [
                "always",
                "never",
                "ignore"
              ]
            },
            "objects": {
              "type": "string",
              "enum": [
                "always",
                "never",
                "ignore"
              ]
            },
            "typeLiterals": {
              "type": "string",
              "enum": [
                "always",
                "never",
                "ignore"
              ]
            }
          }
        }
      ]
    },
    "singleline": {
      "anyOf": [
        {
          "type": "string",
          "enum": [
            "always",
            "never"
          ]
        },
        {
          "type": "object",
          "properties": {
            "arrays": {
              "type": "string",
              "enum": [
                "always",
                "never",
                "ignore"
              ]
            },
            "exports": {
              "type": "string",
              "enum": [
                "always",
                "never",
                "ignore"
              ]
            },
            "functions": {
              "type": "string",
              "enum": [
                "always",
                "never",
                "ignore"
              ]
            },
            "imports": {
              "type": "string",
              "enum": [
                "always",
                "never",
                "ignore"
              ]
            },
            "objects": {
              "type": "string",
              "enum": [
                "always",
                "never",
                "ignore"
              ]
            },
            "typeLiterals": {
              "type": "string",
              "enum": [
                "always",
                "never",
                "ignore"
              ]
            }
          }
        }
      ]
    },
    "esSpecCompliant": {
      "type": "boolean"
    }
  },
  "additionalProperties": false
}