@typescript-eslint/eslint-plugin
Version:
TypeScript plugin for ESLint
117 lines (116 loc) • 5.32 kB
JavaScript
"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const utils_1 = require("@typescript-eslint/utils");
const util_1 = require("../util");
exports.default = (0, util_1.createRule)({
name: 'prefer-literal-enum-member',
meta: {
type: 'suggestion',
docs: {
description: 'Require all enum members to be literal values',
recommended: 'strict',
requiresTypeChecking: false,
},
messages: {
notLiteral: `Explicit enum value must only be a literal value (string or number).`,
notLiteralOrBitwiseExpression: `Explicit enum value must only be a literal value (string or number) or a bitwise expression.`,
},
schema: [
{
type: 'object',
additionalProperties: false,
properties: {
allowBitwiseExpressions: {
type: 'boolean',
description: 'Whether to allow using bitwise expressions in enum initializers.',
},
},
},
],
},
defaultOptions: [
{
allowBitwiseExpressions: false,
},
],
create(context, [{ allowBitwiseExpressions }]) {
function isIdentifierWithName(node, name) {
return node.type === utils_1.AST_NODE_TYPES.Identifier && node.name === name;
}
function hasEnumMember(decl, name) {
return decl.body.members.some(member => isIdentifierWithName(member.id, name) ||
(member.id.type === utils_1.AST_NODE_TYPES.Literal &&
(0, util_1.getStaticStringValue)(member.id) === name));
}
function isSelfEnumMember(decl, node) {
if (node.type === utils_1.AST_NODE_TYPES.Identifier) {
return hasEnumMember(decl, node.name);
}
if (node.type === utils_1.AST_NODE_TYPES.MemberExpression &&
isIdentifierWithName(node.object, decl.id.name)) {
if (node.property.type === utils_1.AST_NODE_TYPES.Identifier) {
return hasEnumMember(decl, node.property.name);
}
if (node.computed) {
const propertyName = (0, util_1.getStaticStringValue)(node.property);
if (propertyName) {
return hasEnumMember(decl, propertyName);
}
}
}
return false;
}
return {
TSEnumMember(node) {
// If there is no initializer, then this node is just the name of the member, so ignore.
if (node.initializer == null) {
return;
}
const declaration = node.parent.parent;
function isAllowedInitializerExpressionRecursive(node, partOfBitwiseComputation) {
// You can only refer to an enum member if it's part of a bitwise computation.
// so C = B isn't allowed (special case), but C = A | B is.
if (partOfBitwiseComputation && isSelfEnumMember(declaration, node)) {
return true;
}
switch (node.type) {
// any old literal
case utils_1.AST_NODE_TYPES.Literal:
return true;
// TemplateLiteral without expressions
case utils_1.AST_NODE_TYPES.TemplateLiteral:
return node.expressions.length === 0;
case utils_1.AST_NODE_TYPES.UnaryExpression:
// +123, -123, etc.
if (['-', '+'].includes(node.operator)) {
return isAllowedInitializerExpressionRecursive(node.argument, partOfBitwiseComputation);
}
if (allowBitwiseExpressions) {
return (node.operator === '~' &&
isAllowedInitializerExpressionRecursive(node.argument, true));
}
return false;
case utils_1.AST_NODE_TYPES.BinaryExpression:
if (allowBitwiseExpressions) {
return (['&', '^', '<<', '>>', '>>>', '|'].includes(node.operator) &&
isAllowedInitializerExpressionRecursive(node.left, true) &&
isAllowedInitializerExpressionRecursive(node.right, true));
}
return false;
default:
return false;
}
}
if (isAllowedInitializerExpressionRecursive(node.initializer, false)) {
return;
}
context.report({
node: node.id,
messageId: allowBitwiseExpressions
? 'notLiteralOrBitwiseExpression'
: 'notLiteral',
});
},
};
},
});