@typescript-eslint/eslint-plugin
Version:
TypeScript plugin for ESLint
120 lines (119 loc) • 5.05 kB
JavaScript
;
var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
if (k2 === undefined) k2 = k;
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Object.defineProperty(o, k2, desc);
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o[k2] = m[k];
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var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
Object.defineProperty(o, "default", { enumerable: true, value: v });
}) : function(o, v) {
o["default"] = v;
});
var __importStar = (this && this.__importStar) || (function () {
var ownKeys = function(o) {
ownKeys = Object.getOwnPropertyNames || function (o) {
var ar = [];
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__setModuleDefault(result, mod);
return result;
};
})();
Object.defineProperty(exports, "__esModule", { value: true });
const utils_1 = require("@typescript-eslint/utils");
const node_path_1 = require("node:path");
const ts = __importStar(require("typescript"));
const util_1 = require("../util");
exports.default = (0, util_1.createRule)({
name: 'no-unnecessary-type-constraint',
meta: {
type: 'suggestion',
docs: {
description: 'Disallow unnecessary constraints on generic types',
recommended: 'recommended',
},
hasSuggestions: true,
messages: {
removeUnnecessaryConstraint: 'Remove the unnecessary `{{constraint}}` constraint.',
unnecessaryConstraint: 'Constraining the generic type `{{name}}` to `{{constraint}}` does nothing and is unnecessary.',
},
schema: [],
},
defaultOptions: [],
create(context) {
// In theory, we could use the type checker for more advanced constraint types...
// ...but in practice, these types are rare, and likely not worth requiring type info.
// https://github.com/typescript-eslint/typescript-eslint/pull/2516#discussion_r495731858
const unnecessaryConstraints = new Map([
[utils_1.AST_NODE_TYPES.TSAnyKeyword, 'any'],
[utils_1.AST_NODE_TYPES.TSUnknownKeyword, 'unknown'],
]);
function checkRequiresGenericDeclarationDisambiguation(filename) {
const pathExt = (0, node_path_1.extname)(filename).toLocaleLowerCase();
switch (pathExt) {
case ts.Extension.Cts:
case ts.Extension.Mts:
case ts.Extension.Tsx:
return true;
default:
return false;
}
}
const requiresGenericDeclarationDisambiguation = checkRequiresGenericDeclarationDisambiguation(context.filename);
const checkNode = (node, inArrowFunction) => {
const constraint = unnecessaryConstraints.get(node.constraint.type);
function shouldAddTrailingComma() {
if (!inArrowFunction || !requiresGenericDeclarationDisambiguation) {
return false;
}
// Only <T>() => {} would need trailing comma
return (node.parent.params.length ===
1 &&
context.sourceCode.getTokensAfter(node)[0].value !== ',' &&
!node.default);
}
if (constraint) {
context.report({
node,
messageId: 'unnecessaryConstraint',
data: {
name: node.name.name,
constraint,
},
suggest: [
{
messageId: 'removeUnnecessaryConstraint',
data: {
constraint,
},
fix(fixer) {
return fixer.replaceTextRange([node.name.range[1], node.constraint.range[1]], shouldAddTrailingComma() ? ',' : '');
},
},
],
});
}
};
return {
':not(ArrowFunctionExpression) > TSTypeParameterDeclaration > TSTypeParameter[constraint]'(node) {
checkNode(node, false);
},
'ArrowFunctionExpression > TSTypeParameterDeclaration > TSTypeParameter[constraint]'(node) {
checkNode(node, true);
},
};
},
});