124 lines
4.9 KiB
JavaScript
124 lines
4.9 KiB
JavaScript
"use strict";
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/**
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* @license
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* Copyright 2017 Palantir Technologies, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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Object.defineProperty(exports, "__esModule", { value: true });
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var tslib_1 = require("tslib");
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var tsutils_1 = require("tsutils");
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var ts = require("typescript");
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var Lint = require("../index");
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var OPTION_SINGLE_CONCAT = "allow-single-concat";
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var Rule = (function (_super) {
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tslib_1.__extends(Rule, _super);
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function Rule() {
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return _super !== null && _super.apply(this, arguments) || this;
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}
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Rule.prototype.apply = function (sourceFile) {
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if (sourceFile.isDeclarationFile) {
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return []; // Not possible in a declaration file
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}
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var allowSingleConcat = this.ruleArguments.indexOf(OPTION_SINGLE_CONCAT) !== -1;
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return this.applyWithFunction(sourceFile, function (ctx) { return walk(ctx, allowSingleConcat); });
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};
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return Rule;
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}(Lint.Rules.AbstractRule));
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/* tslint:disable:object-literal-sort-keys */
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Rule.metadata = {
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ruleName: "prefer-template",
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description: "Prefer a template expression over string literal concatenation.",
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optionsDescription: (_a = ["\n If `", "` is specified, then a single concatenation (`x + y`) is allowed, but not more (`x + y + z`)."], _a.raw = ["\n If \\`", "\\` is specified, then a single concatenation (\\`x + y\\`) is allowed, but not more (\\`x + y + z\\`)."], Lint.Utils.dedent(_a, OPTION_SINGLE_CONCAT)),
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options: {
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type: "string",
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enum: [OPTION_SINGLE_CONCAT],
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},
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optionExamples: [true, [true, OPTION_SINGLE_CONCAT]],
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type: "style",
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typescriptOnly: false,
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};
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/* tslint:enable:object-literal-sort-keys */
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Rule.FAILURE_STRING = "Use a template literal instead of concatenating with a string literal.";
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Rule.FAILURE_STRING_MULTILINE = "Use a multiline template literal instead of concatenating string literals with newlines.";
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exports.Rule = Rule;
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function walk(ctx, allowSingleConcat) {
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return ts.forEachChild(ctx.sourceFile, function cb(node) {
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var failure = getError(node, allowSingleConcat);
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if (failure !== undefined) {
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ctx.addFailureAtNode(node, failure);
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}
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else {
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return ts.forEachChild(node, cb);
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}
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});
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}
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function getError(node, allowSingleConcat) {
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if (!isPlusExpression(node)) {
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return undefined;
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}
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var left = node.left, right = node.right;
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var l = isStringLike(left);
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var r = isStringLike(right);
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if (l && r) {
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// They're both strings.
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// If they're joined by a newline, recommend a template expression instead.
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// Otherwise ignore. ("a" + "b", probably writing a long newline-less string on many lines.)
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return containsNewline(left) || containsNewline(right) ? Rule.FAILURE_STRING_MULTILINE : undefined;
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}
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else if (!l && !r) {
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// Watch out for `"a" + b + c`. Parsed as `("a" + b) + c`.
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return containsAnyStringLiterals(left) ? Rule.FAILURE_STRING : undefined;
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}
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else if (l) {
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// `"x" + y`
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return !allowSingleConcat ? Rule.FAILURE_STRING : undefined;
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}
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else {
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// `? + "b"`
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// If LHS consists of only string literals (as in `"a" + "b" + "c"`, allow it.)
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return !containsOnlyStringLiterals(left) && (!allowSingleConcat || isPlusExpression(left)) ? Rule.FAILURE_STRING : undefined;
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}
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}
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function containsNewline(node) {
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if (node.kind === ts.SyntaxKind.TemplateExpression) {
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return node.templateSpans.some(function (_a) {
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var text = _a.literal.text;
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return text.includes("\n");
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});
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}
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else {
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return node.text.includes("\n");
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}
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}
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function containsOnlyStringLiterals(node) {
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return isPlusExpression(node) && isStringLike(node.right) && (isStringLike(node.left) || containsAnyStringLiterals(node.left));
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}
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function containsAnyStringLiterals(node) {
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return isPlusExpression(node) && (isStringLike(node.right) || isStringLike(node.left) || containsAnyStringLiterals(node.left));
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}
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function isPlusExpression(node) {
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return tsutils_1.isBinaryExpression(node) && node.operatorToken.kind === ts.SyntaxKind.PlusToken;
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}
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function isStringLike(node) {
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switch (node.kind) {
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case ts.SyntaxKind.StringLiteral:
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case ts.SyntaxKind.NoSubstitutionTemplateLiteral:
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case ts.SyntaxKind.TemplateExpression:
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return true;
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default:
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return false;
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}
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}
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var _a;
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