📄 `getFunctionHeadLoc`¶

📊 Analysis Summary¶

Metric	Count
🔧 Functions	2
📦 Imports	6
📑 Type Aliases	1

📚 Table of Contents¶

Imports
Functions
Type Aliases

🛠️ File Location:¶

📂 packages/eslint-plugin/src/util/getFunctionHeadLoc.ts

📦 Imports¶

Name	Source
`TSESLint`	`@typescript-eslint/utils`
`TSESTree`	`@typescript-eslint/utils`
`AST_NODE_TYPES`	`@typescript-eslint/utils`
`ESLintUtils`	`@typescript-eslint/utils`
`isArrowToken`	`./astUtils`
`isOpeningParenToken`	`./astUtils`

Functions¶

`getFunctionHeadLoc(node: FunctionNode, sourceCode: TSESLint.SourceCode): TSESTree.SourceLocation`¶

Gets the location of the given function node for reporting.

function foo() {} ^^^^^^^^^^^^
(function foo() {}) ^^^^^^^^^^^^
(function() {}) ^^^^^^^^
function* foo() {} ^^^^^^^^^^^^^
(function* foo() {}) ^^^^^^^^^^^^^
(function*() {}) ^^^^^^^^^
() => {} ^^
async () => {} ^^
({ foo: function foo() {} }) ^^^^^^^^^^^^^^^^^
({ foo: function() {} }) ^^^^^^^^^^^^^
({ ['foo']: function() {} }) ^^^^^^^^^^^^^^^^^
({ [foo]: function() {} }) ^^^^^^^^^^^^^^^
({ foo() {} }) ^^^
({ foo: function* foo() {} }) ^^^^^^^^^^^^^^^^^^
({ foo: function*() {} }) ^^^^^^^^^^^^^^
({ ['foo']: function*() {} }) ^^^^^^^^^^^^^^^^^^
({ [foo]: function*() {} }) ^^^^^^^^^^^^^^^^
({ *foo() {} }) ^^^^
({ foo: async function foo() {} }) ^^^^^^^^^^^^^^^^^^^^^^^
({ foo: async function() {} }) ^^^^^^^^^^^^^^^^^^^
({ ['foo']: async function() {} }) ^^^^^^^^^^^^^^^^^^^^^^^
({ [foo]: async function() {} }) ^^^^^^^^^^^^^^^^^^^^^
({ async foo() {} }) ^^^^^^^^^
({ get foo() {} }) ^^^^^^^
({ set foo(a) {} }) ^^^^^^^
class A { constructor() {} } ^^^^^^^^^^^
class A { foo() {} } ^^^
class A { *foo() {} } ^^^^
class A { async foo() {} } ^^^^^^^^^
class A { ['foo']() {} } ^^^^^^^
class A { *['foo']() {} } ^^^^^^^^
class A { async ['foo']() {} } ^^^^^^^^^^^^^
class A { [foo]() {} } ^^^^^
class A { *[foo]() {} } ^^^^^^
class A { async [foo]() {} } ^^^^^^^^^^^
class A { get foo() {} } ^^^^^^^
class A { set foo(a) {} } ^^^^^^^
class A { static foo() {} } ^^^^^^^^^^
class A { static *foo() {} } ^^^^^^^^^^^
class A { static async foo() {} } ^^^^^^^^^^^^^^^^
class A { static get foo() {} } ^^^^^^^^^^^^^^
class A { static set foo(a) {} } ^^^^^^^^^^^^^^
class A { foo = function() {} } ^^^^^^^^^^^^^^
class A { static foo = function() {} } ^^^^^^^^^^^^^^^^^^^^^
class A { foo = (a, b) => {} } ^^^^^^

Parameters:

node any: The function node to get.
sourceCode any: The source code object to get tokens.

Returns: undefined The location of the function node for reporting.

Raw JSDoc

/**
 * Gets the location of the given function node for reporting.
 *
 * - `function foo() {}`
 *    ^^^^^^^^^^^^
 * - `(function foo() {})`
 *     ^^^^^^^^^^^^
 * - `(function() {})`
 *     ^^^^^^^^
 * - `function* foo() {}`
 *    ^^^^^^^^^^^^^
 * - `(function* foo() {})`
 *     ^^^^^^^^^^^^^
 * - `(function*() {})`
 *     ^^^^^^^^^
 * - `() => {}`
 *       ^^
 * - `async () => {}`
 *             ^^
 * - `({ foo: function foo() {} })`
 *       ^^^^^^^^^^^^^^^^^
 * - `({ foo: function() {} })`
 *       ^^^^^^^^^^^^^
 * - `({ ['foo']: function() {} })`
 *       ^^^^^^^^^^^^^^^^^
 * - `({ [foo]: function() {} })`
 *       ^^^^^^^^^^^^^^^
 * - `({ foo() {} })`
 *       ^^^
 * - `({ foo: function* foo() {} })`
 *       ^^^^^^^^^^^^^^^^^^
 * - `({ foo: function*() {} })`
 *       ^^^^^^^^^^^^^^
 * - `({ ['foo']: function*() {} })`
 *       ^^^^^^^^^^^^^^^^^^
 * - `({ [foo]: function*() {} })`
 *       ^^^^^^^^^^^^^^^^
 * - `({ *foo() {} })`
 *       ^^^^
 * - `({ foo: async function foo() {} })`
 *       ^^^^^^^^^^^^^^^^^^^^^^^
 * - `({ foo: async function() {} })`
 *       ^^^^^^^^^^^^^^^^^^^
 * - `({ ['foo']: async function() {} })`
 *       ^^^^^^^^^^^^^^^^^^^^^^^
 * - `({ [foo]: async function() {} })`
 *       ^^^^^^^^^^^^^^^^^^^^^
 * - `({ async foo() {} })`
 *       ^^^^^^^^^
 * - `({ get foo() {} })`
 *       ^^^^^^^
 * - `({ set foo(a) {} })`
 *       ^^^^^^^
 * - `class A { constructor() {} }`
 *              ^^^^^^^^^^^
 * - `class A { foo() {} }`
 *              ^^^
 * - `class A { *foo() {} }`
 *              ^^^^
 * - `class A { async foo() {} }`
 *              ^^^^^^^^^
 * - `class A { ['foo']() {} }`
 *              ^^^^^^^
 * - `class A { *['foo']() {} }`
 *              ^^^^^^^^
 * - `class A { async ['foo']() {} }`
 *              ^^^^^^^^^^^^^
 * - `class A { [foo]() {} }`
 *              ^^^^^
 * - `class A { *[foo]() {} }`
 *              ^^^^^^
 * - `class A { async [foo]() {} }`
 *              ^^^^^^^^^^^
 * - `class A { get foo() {} }`
 *              ^^^^^^^
 * - `class A { set foo(a) {} }`
 *              ^^^^^^^
 * - `class A { static foo() {} }`
 *              ^^^^^^^^^^
 * - `class A { static *foo() {} }`
 *              ^^^^^^^^^^^
 * - `class A { static async foo() {} }`
 *              ^^^^^^^^^^^^^^^^
 * - `class A { static get foo() {} }`
 *              ^^^^^^^^^^^^^^
 * - `class A { static set foo(a) {} }`
 *              ^^^^^^^^^^^^^^
 * - `class A { foo = function() {} }`
 *              ^^^^^^^^^^^^^^
 * - `class A { static foo = function() {} }`
 *              ^^^^^^^^^^^^^^^^^^^^^
 * - `class A { foo = (a, b) => {} }`
 *              ^^^^^^
 * @param node The function node to get.
 * @param sourceCode The source code object to get tokens.
 * @returns The location of the function node for reporting.
 */

Calls:

ESLintUtils.nullThrows
sourceCode.getTokenAfter
ESLintUtils.NullThrowsReasons.MissingToken
getOpeningParenOfParams
sourceCode.getTokenBefore

Internal Comments:

// the decorator's range is included within the member
// however it's usually irrelevant to the member itself - so we don't want
// to highlight it ever.

Code

export function getFunctionHeadLoc(
  node: FunctionNode,
  sourceCode: TSESLint.SourceCode,
): TSESTree.SourceLocation {
  const parent = node.parent;
  let start: TSESTree.Position;
  let end: TSESTree.Position;

  if (
    parent.type === AST_NODE_TYPES.MethodDefinition ||
    parent.type === AST_NODE_TYPES.PropertyDefinition
  ) {
    // the decorator's range is included within the member
    // however it's usually irrelevant to the member itself - so we don't want
    // to highlight it ever.
    if (parent.decorators.length > 0) {
      const lastDecorator = parent.decorators[parent.decorators.length - 1];
      const firstTokenAfterDecorator = ESLintUtils.nullThrows(
        sourceCode.getTokenAfter(lastDecorator),
        ESLintUtils.NullThrowsReasons.MissingToken(
          'modifier or member name',
          'class member',
        ),
      );
      start = firstTokenAfterDecorator.loc.start;
    } else {
      start = parent.loc.start;
    }
    end = getOpeningParenOfParams(node, sourceCode).loc.start;
  } else if (parent.type === AST_NODE_TYPES.Property) {
    start = parent.loc.start;
    end = getOpeningParenOfParams(node, sourceCode).loc.start;
  } else if (node.type === AST_NODE_TYPES.ArrowFunctionExpression) {
    const arrowToken = ESLintUtils.nullThrows(
      sourceCode.getTokenBefore(node.body, isArrowToken),
      ESLintUtils.NullThrowsReasons.MissingToken(
        'arrow token',
        'arrow function',
      ),
    );

    start = arrowToken.loc.start;
    end = arrowToken.loc.end;
  } else {
    start = node.loc.start;
    end = getOpeningParenOfParams(node, sourceCode).loc.start;
  }

  return {
    end: { ...end },
    start: { ...start },
  };
}

`getOpeningParenOfParams(node: FunctionNode, sourceCode: TSESLint.SourceCode): TSESTree.Token`¶

Gets the ( token of the given function node.

Parameters:

node any: The function node to get.
sourceCode any: The source code object to get tokens.

Returns: undefined ( token.

Raw JSDoc

/**
 * Gets the `(` token of the given function node.
 * @param node The function node to get.
 * @param sourceCode The source code object to get tokens.
 * @returns `(` token.
 */

Calls:

ESLintUtils.nullThrows
sourceCode.getFirstToken
ESLintUtils.NullThrowsReasons.MissingToken
sourceCode.getTokenBefore
isOpeningParenToken (from ./astUtils)
sourceCode.getTokenAfter

Internal Comments:

// If the node is an arrow function and doesn't have parens, this returns the identifier of the first param.
// Otherwise, returns paren.

Code

function getOpeningParenOfParams(
  node: FunctionNode,
  sourceCode: TSESLint.SourceCode,
): TSESTree.Token {
  // If the node is an arrow function and doesn't have parens, this returns the identifier of the first param.
  if (
    node.type === AST_NODE_TYPES.ArrowFunctionExpression &&
    node.params.length === 1
  ) {
    const argToken = ESLintUtils.nullThrows(
      sourceCode.getFirstToken(node.params[0]),
      ESLintUtils.NullThrowsReasons.MissingToken('parameter', 'arrow function'),
    );
    const maybeParenToken = sourceCode.getTokenBefore(argToken);

    return maybeParenToken && isOpeningParenToken(maybeParenToken)
      ? maybeParenToken
      : argToken;
  }

  // Otherwise, returns paren.
  return node.id != null
    ? ESLintUtils.nullThrows(
        sourceCode.getTokenAfter(node.id, isOpeningParenToken),
        ESLintUtils.NullThrowsReasons.MissingToken('id', 'function'),
      )
    : ESLintUtils.nullThrows(
        sourceCode.getFirstToken(node, isOpeningParenToken),
        ESLintUtils.NullThrowsReasons.MissingToken(
          'opening parenthesis',
          'function',
        ),
      );
}

Type Aliases¶

`FunctionNode`¶

type FunctionNode = | TSESTree.ArrowFunctionExpression
  | TSESTree.FunctionDeclaration
  | TSESTree.FunctionExpression;

Generated by Syntax Scribe

📄 getFunctionHeadLoc¶