github-pages-deploy-action/node_modules/tslint/lib/rules/noNullKeywordRule.js
2019-11-19 07:48:29 -05:00

72 lines
4.6 KiB
JavaScript

"use strict";
/**
* @license
* Copyright 2013 Palantir Technologies, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
Object.defineProperty(exports, "__esModule", { value: true });
var tslib_1 = require("tslib");
// with due reference to https://github.com/Microsoft/TypeScript/blob/7813121c4d77e50aad0eed3152ef1f1156c7b574/scripts/tslint/noNullRule.ts
var tsutils_1 = require("tsutils");
var ts = require("typescript");
var Lint = require("../index");
var Rule = /** @class */ (function (_super) {
tslib_1.__extends(Rule, _super);
function Rule() {
return _super !== null && _super.apply(this, arguments) || this;
}
Rule.prototype.apply = function (sourceFile) {
return this.applyWithFunction(sourceFile, walk);
};
/* tslint:disable:object-literal-sort-keys */
Rule.metadata = {
ruleName: "no-null-keyword",
description: "Disallows use of the `null` keyword literal.",
rationale: Lint.Utils.dedent(templateObject_1 || (templateObject_1 = tslib_1.__makeTemplateObject(["\n Instead of having the dual concepts of `null` and`undefined` in a codebase,\n this rule ensures that only `undefined` is used.\n\n JavaScript originally intended `undefined` to refer to a value that doesn't yet exist,\n while `null` was meant to refer to a value that does exist but points to nothing.\n That's confusing.\n `undefined` is the default value when object members don't exist, and is the return value\n for newer native collection APIs such as `Map.get` when collection values don't exist.\n\n ```\n const myObject = {};\n myObject.doesNotExist; // undefined\n ```\n\n ```\n const myMap = new Map<string, number>();\n myMap.get(\"doesNotExist\"); // undefined\n ```\n\n To remove confusion over the two similar values, it's better to stick with just `undefined`.\n "], ["\n Instead of having the dual concepts of \\`null\\` and\\`undefined\\` in a codebase,\n this rule ensures that only \\`undefined\\` is used.\n\n JavaScript originally intended \\`undefined\\` to refer to a value that doesn't yet exist,\n while \\`null\\` was meant to refer to a value that does exist but points to nothing.\n That's confusing.\n \\`undefined\\` is the default value when object members don't exist, and is the return value\n for newer native collection APIs such as \\`Map.get\\` when collection values don't exist.\n\n \\`\\`\\`\n const myObject = {};\n myObject.doesNotExist; // undefined\n \\`\\`\\`\n\n \\`\\`\\`\n const myMap = new Map<string, number>();\n myMap.get(\"doesNotExist\"); // undefined\n \\`\\`\\`\n\n To remove confusion over the two similar values, it's better to stick with just \\`undefined\\`.\n "]))),
optionsDescription: "Not configurable.",
options: null,
optionExamples: [true],
type: "functionality",
typescriptOnly: false,
hasFix: true,
};
/* tslint:enable:object-literal-sort-keys */
Rule.FAILURE_STRING = "Use 'undefined' instead of 'null'";
return Rule;
}(Lint.Rules.AbstractRule));
exports.Rule = Rule;
function walk(ctx) {
return ts.forEachChild(ctx.sourceFile, cb);
function cb(node) {
if (tsutils_1.isTypeNodeKind(node.kind)) {
return; // skip type nodes
}
if (node.kind !== ts.SyntaxKind.NullKeyword) {
return ts.forEachChild(node, cb);
}
var parent = node.parent;
var eq;
if (tsutils_1.isBinaryExpression(parent)) {
eq = Lint.getEqualsKind(parent.operatorToken);
}
if (eq === undefined) {
ctx.addFailureAtNode(node, Rule.FAILURE_STRING);
}
else if (!eq.isStrict) {
ctx.addFailureAtNode(node, Rule.FAILURE_STRING, Lint.Replacement.replaceNode(node, "undefined", ctx.sourceFile));
}
}
}
var templateObject_1;