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/**
* @fileoverview Rule to flag non-camelcased identifiers
* @author Nicholas C. Zakas
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const astUtils = require("./utils/ast-utils");
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
/** @type {import('../shared/types').Rule} */
module.exports = {
meta: {
type: "suggestion",
docs: {
description: "Enforce camelcase naming convention",
recommended: false,
url: "https://eslint.org/docs/rules/camelcase"
},
schema: [
{
type: "object",
properties: {
ignoreDestructuring: {
type: "boolean",
default: false
},
ignoreImports: {
type: "boolean",
default: false
},
ignoreGlobals: {
type: "boolean",
default: false
},
properties: {
enum: ["always", "never"]
},
allow: {
type: "array",
items: [
{
type: "string"
}
],
minItems: 0,
uniqueItems: true
}
},
additionalProperties: false
}
],
messages: {
notCamelCase: "Identifier '{{name}}' is not in camel case.",
notCamelCasePrivate: "#{{name}} is not in camel case."
}
},
create(context) {
const options = context.options[0] || {};
const properties = options.properties === "never" ? "never" : "always";
const ignoreDestructuring = options.ignoreDestructuring;
const ignoreImports = options.ignoreImports;
const ignoreGlobals = options.ignoreGlobals;
const allow = options.allow || [];
//--------------------------------------------------------------------------
// Helpers
//--------------------------------------------------------------------------
// contains reported nodes to avoid reporting twice on destructuring with shorthand notation
const reported = new Set();
/**
* Checks if a string contains an underscore and isn't all upper-case
* @param {string} name The string to check.
* @returns {boolean} if the string is underscored
* @private
*/
function isUnderscored(name) {
const nameBody = name.replace(/^_+|_+$/gu, "");
// if there's an underscore, it might be A_CONSTANT, which is okay
return nameBody.includes("_") && nameBody !== nameBody.toUpperCase();
}
/**
* Checks if a string match the ignore list
* @param {string} name The string to check.
* @returns {boolean} if the string is ignored
* @private
*/
function isAllowed(name) {
return allow.some(
entry => name === entry || name.match(new RegExp(entry, "u"))
);
}
/**
* Checks if a given name is good or not.
* @param {string} name The name to check.
* @returns {boolean} `true` if the name is good.
* @private
*/
function isGoodName(name) {
return !isUnderscored(name) || isAllowed(name);
}
/**
* Checks if a given identifier reference or member expression is an assignment
* target.
* @param {ASTNode} node The node to check.
* @returns {boolean} `true` if the node is an assignment target.
*/
function isAssignmentTarget(node) {
const parent = node.parent;
switch (parent.type) {
case "AssignmentExpression":
case "AssignmentPattern":
return parent.left === node;
case "Property":
return (
parent.parent.type === "ObjectPattern" &&
parent.value === node
);
case "ArrayPattern":
case "RestElement":
return true;
default:
return false;
}
}
/**
* Checks if a given binding identifier uses the original name as-is.
* - If it's in object destructuring or object expression, the original name is its property name.
* - If it's in import declaration, the original name is its exported name.
* @param {ASTNode} node The `Identifier` node to check.
* @returns {boolean} `true` if the identifier uses the original name as-is.
*/
function equalsToOriginalName(node) {
const localName = node.name;
const valueNode = node.parent.type === "AssignmentPattern"
? node.parent
: node;
const parent = valueNode.parent;
switch (parent.type) {
case "Property":
return (
(parent.parent.type === "ObjectPattern" || parent.parent.type === "ObjectExpression") &&
parent.value === valueNode &&
!parent.computed &&
parent.key.type === "Identifier" &&
parent.key.name === localName
);
case "ImportSpecifier":
return (
parent.local === node &&
astUtils.getModuleExportName(parent.imported) === localName
);
default:
return false;
}
}
/**
* Reports an AST node as a rule violation.
* @param {ASTNode} node The node to report.
* @returns {void}
* @private
*/
function report(node) {
if (reported.has(node.range[0])) {
return;
}
reported.add(node.range[0]);
// Report it.
context.report({
node,
messageId: node.type === "PrivateIdentifier"
? "notCamelCasePrivate"
: "notCamelCase",
data: { name: node.name }
});
}
/**
* Reports an identifier reference or a binding identifier.
* @param {ASTNode} node The `Identifier` node to report.
* @returns {void}
*/
function reportReferenceId(node) {
/*
* For backward compatibility, if it's in callings then ignore it.
* Not sure why it is.
*/
if (
node.parent.type === "CallExpression" ||
node.parent.type === "NewExpression"
) {
return;
}
/*
* For backward compatibility, if it's a default value of
* destructuring/parameters then ignore it.
* Not sure why it is.
*/
if (
node.parent.type === "AssignmentPattern" &&
node.parent.right === node
) {
return;
}
/*
* The `ignoreDestructuring` flag skips the identifiers that uses
* the property name as-is.
*/
if (ignoreDestructuring && equalsToOriginalName(node)) {
return;
}
report(node);
}
return {
// Report camelcase of global variable references ------------------
Program() {
const scope = context.getScope();
if (!ignoreGlobals) {
// Defined globals in config files or directive comments.
for (const variable of scope.variables) {
if (
variable.identifiers.length > 0 ||
isGoodName(variable.name)
) {
continue;
}
for (const reference of variable.references) {
/*
* For backward compatibility, this rule reports read-only
* references as well.
*/
reportReferenceId(reference.identifier);
}
}
}
// Undefined globals.
for (const reference of scope.through) {
const id = reference.identifier;
if (isGoodName(id.name)) {
continue;
}
/*
* For backward compatibility, this rule reports read-only
* references as well.
*/
reportReferenceId(id);
}
},
// Report camelcase of declared variables --------------------------
[[
"VariableDeclaration",
"FunctionDeclaration",
"FunctionExpression",
"ArrowFunctionExpression",
"ClassDeclaration",
"ClassExpression",
"CatchClause"
]](node) {
for (const variable of context.getDeclaredVariables(node)) {
if (isGoodName(variable.name)) {
continue;
}
const id = variable.identifiers[0];
// Report declaration.
if (!(ignoreDestructuring && equalsToOriginalName(id))) {
report(id);
}
/*
* For backward compatibility, report references as well.
* It looks unnecessary because declarations are reported.
*/
for (const reference of variable.references) {
if (reference.init) {
continue; // Skip the write references of initializers.
}
reportReferenceId(reference.identifier);
}
}
},
// Report camelcase in properties ----------------------------------
[[
"ObjectExpression > Property[computed!=true] > Identifier.key",
"MethodDefinition[computed!=true] > Identifier.key",
"PropertyDefinition[computed!=true] > Identifier.key",
"MethodDefinition > PrivateIdentifier.key",
"PropertyDefinition > PrivateIdentifier.key"
]](node) {
if (properties === "never" || isGoodName(node.name)) {
return;
}
report(node);
},
"MemberExpression[computed!=true] > Identifier.property"(node) {
if (
properties === "never" ||
!isAssignmentTarget(node.parent) || // ← ignore read-only references.
isGoodName(node.name)
) {
return;
}
report(node);
},
// Report camelcase in import --------------------------------------
ImportDeclaration(node) {
for (const variable of context.getDeclaredVariables(node)) {
if (isGoodName(variable.name)) {
continue;
}
const id = variable.identifiers[0];
// Report declaration.
if (!(ignoreImports && equalsToOriginalName(id))) {
report(id);
}
/*
* For backward compatibility, report references as well.
* It looks unnecessary because declarations are reported.
*/
for (const reference of variable.references) {
reportReferenceId(reference.identifier);
}
}
},
// Report camelcase in re-export -----------------------------------
[[
"ExportAllDeclaration > Identifier.exported",
"ExportSpecifier > Identifier.exported"
]](node) {
if (isGoodName(node.name)) {
return;
}
report(node);
},
// Report camelcase in labels --------------------------------------
[[
"LabeledStatement > Identifier.label",
/*
* For backward compatibility, report references as well.
* It looks unnecessary because declarations are reported.
*/
"BreakStatement > Identifier.label",
"ContinueStatement > Identifier.label"
]](node) {
if (isGoodName(node.name)) {
return;
}
report(node);
}
};
}
};