/node_modules/eslint/lib/rules/no-underscore-dangle.js
JavaScript | 203 lines | 117 code | 24 blank | 62 comment | 21 complexity | 58659753ec4842e38774864b07832f67 MD5 | raw file
Possible License(s): Apache-2.0, GPL-2.0, BSD-3-Clause, 0BSD, MIT, JSON, CC-BY-SA-3.0, CC-BY-4.0, BSD-2-Clause, Unlicense
- /**
- * @fileoverview Rule to flag trailing underscores in variable declarations.
- * @author Matt DuVall <http://www.mattduvall.com>
- */
- "use strict";
- //------------------------------------------------------------------------------
- // Rule Definition
- //------------------------------------------------------------------------------
- module.exports = {
- meta: {
- docs: {
- description: "disallow dangling underscores in identifiers",
- category: "Stylistic Issues",
- recommended: false
- },
- schema: [
- {
- type: "object",
- properties: {
- allow: {
- type: "array",
- items: {
- type: "string"
- }
- },
- allowAfterThis: {
- type: "boolean"
- },
- allowAfterSuper: {
- type: "boolean"
- },
- enforceInMethodNames: {
- type: "boolean"
- }
- },
- additionalProperties: false
- }
- ]
- },
- create(context) {
- const options = context.options[0] || {};
- const ALLOWED_VARIABLES = options.allow ? options.allow : [];
- const allowAfterThis = typeof options.allowAfterThis !== "undefined" ? options.allowAfterThis : false;
- const allowAfterSuper = typeof options.allowAfterSuper !== "undefined" ? options.allowAfterSuper : false;
- const enforceInMethodNames = typeof options.enforceInMethodNames !== "undefined" ? options.enforceInMethodNames : false;
- //-------------------------------------------------------------------------
- // Helpers
- //-------------------------------------------------------------------------
- /**
- * Check if identifier is present inside the allowed option
- * @param {string} identifier name of the node
- * @returns {boolean} true if its is present
- * @private
- */
- function isAllowed(identifier) {
- return ALLOWED_VARIABLES.some(ident => ident === identifier);
- }
- /**
- * Check if identifier has a underscore at the end
- * @param {ASTNode} identifier node to evaluate
- * @returns {boolean} true if its is present
- * @private
- */
- function hasTrailingUnderscore(identifier) {
- const len = identifier.length;
- return identifier !== "_" && (identifier[0] === "_" || identifier[len - 1] === "_");
- }
- /**
- * Check if identifier is a special case member expression
- * @param {ASTNode} identifier node to evaluate
- * @returns {boolean} true if its is a special case
- * @private
- */
- function isSpecialCaseIdentifierForMemberExpression(identifier) {
- return identifier === "__proto__";
- }
- /**
- * Check if identifier is a special case variable expression
- * @param {ASTNode} identifier node to evaluate
- * @returns {boolean} true if its is a special case
- * @private
- */
- function isSpecialCaseIdentifierInVariableExpression(identifier) {
- // Checks for the underscore library usage here
- return identifier === "_";
- }
- /**
- * Check if function has a underscore at the end
- * @param {ASTNode} node node to evaluate
- * @returns {void}
- * @private
- */
- function checkForTrailingUnderscoreInFunctionDeclaration(node) {
- if (node.id) {
- const identifier = node.id.name;
- if (typeof identifier !== "undefined" && hasTrailingUnderscore(identifier) && !isAllowed(identifier)) {
- context.report({
- node,
- message: "Unexpected dangling '_' in '{{identifier}}'.",
- data: {
- identifier
- }
- });
- }
- }
- }
- /**
- * Check if variable expression has a underscore at the end
- * @param {ASTNode} node node to evaluate
- * @returns {void}
- * @private
- */
- function checkForTrailingUnderscoreInVariableExpression(node) {
- const identifier = node.id.name;
- if (typeof identifier !== "undefined" && hasTrailingUnderscore(identifier) &&
- !isSpecialCaseIdentifierInVariableExpression(identifier) && !isAllowed(identifier)) {
- context.report({
- node,
- message: "Unexpected dangling '_' in '{{identifier}}'.",
- data: {
- identifier
- }
- });
- }
- }
- /**
- * Check if member expression has a underscore at the end
- * @param {ASTNode} node node to evaluate
- * @returns {void}
- * @private
- */
- function checkForTrailingUnderscoreInMemberExpression(node) {
- const identifier = node.property.name,
- isMemberOfThis = node.object.type === "ThisExpression",
- isMemberOfSuper = node.object.type === "Super";
- if (typeof identifier !== "undefined" && hasTrailingUnderscore(identifier) &&
- !(isMemberOfThis && allowAfterThis) &&
- !(isMemberOfSuper && allowAfterSuper) &&
- !isSpecialCaseIdentifierForMemberExpression(identifier) && !isAllowed(identifier)) {
- context.report({
- node,
- message: "Unexpected dangling '_' in '{{identifier}}'.",
- data: {
- identifier
- }
- });
- }
- }
- /**
- * Check if method declaration or method property has a underscore at the end
- * @param {ASTNode} node node to evaluate
- * @returns {void}
- * @private
- */
- function checkForTrailingUnderscoreInMethod(node) {
- const identifier = node.key.name;
- const isMethod = node.type === "MethodDefinition" || node.type === "Property" && node.method;
- if (typeof identifier !== "undefined" && enforceInMethodNames && isMethod && hasTrailingUnderscore(identifier)) {
- context.report({
- node,
- message: "Unexpected dangling '_' in '{{identifier}}'.",
- data: {
- identifier
- }
- });
- }
- }
- //--------------------------------------------------------------------------
- // Public API
- //--------------------------------------------------------------------------
- return {
- FunctionDeclaration: checkForTrailingUnderscoreInFunctionDeclaration,
- VariableDeclarator: checkForTrailingUnderscoreInVariableExpression,
- MemberExpression: checkForTrailingUnderscoreInMemberExpression,
- MethodDefinition: checkForTrailingUnderscoreInMethod,
- Property: checkForTrailingUnderscoreInMethod
- };
- }
- };