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node_modules/tslint/lib/rules/preferTemplateRule.js

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+"use strict";
+/**
+ * @license
+ * Copyright 2017 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");
+var tsutils_1 = require("tsutils");
+var ts = require("typescript");
+var Lint = require("../index");
+var preferTemplate_examples_1 = require("./code-examples/preferTemplate.examples");
+var OPTION_SINGLE_CONCAT = "allow-single-concat";
+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) {
+        if (sourceFile.isDeclarationFile) {
+            return []; // Not possible in a declaration file
+        }
+        var allowSingleConcat = this.ruleArguments.indexOf(OPTION_SINGLE_CONCAT) !== -1;
+        return this.applyWithFunction(sourceFile, walk, { allowSingleConcat: allowSingleConcat });
+    };
+    /* tslint:disable:object-literal-sort-keys */
+    Rule.metadata = {
+        ruleName: "prefer-template",
+        description: "Prefer a template expression over string literal concatenation.",
+        optionsDescription: Lint.Utils.dedent(templateObject_1 || (templateObject_1 = tslib_1.__makeTemplateObject(["\n            If `", "` is specified, then a single concatenation (`x + y`) is allowed, but not more (`x + y + z`)."], ["\n            If \\`", "\\` is specified, then a single concatenation (\\`x + y\\`) is allowed, but not more (\\`x + y + z\\`)."])), OPTION_SINGLE_CONCAT),
+        options: {
+            type: "string",
+            enum: [OPTION_SINGLE_CONCAT],
+        },
+        optionExamples: [true, [true, OPTION_SINGLE_CONCAT]],
+        type: "style",
+        typescriptOnly: false,
+        codeExamples: preferTemplate_examples_1.codeExamples,
+    };
+    /* tslint:enable:object-literal-sort-keys */
+    Rule.FAILURE_STRING = "Use a template literal instead of concatenating with a string literal.";
+    Rule.FAILURE_STRING_MULTILINE = "Use a multiline template literal instead of concatenating string literals with newlines.";
+    return Rule;
+}(Lint.Rules.AbstractRule));
+exports.Rule = Rule;
+function walk(ctx) {
+    var allowSingleConcat = ctx.options.allowSingleConcat;
+    return ts.forEachChild(ctx.sourceFile, function cb(node) {
+        var failure = getError(node, allowSingleConcat);
+        if (failure !== undefined) {
+            ctx.addFailureAtNode(node, failure);
+        }
+        else {
+            return ts.forEachChild(node, cb);
+        }
+    });
+}
+function getError(node, allowSingleConcat) {
+    if (!isPlusExpression(node)) {
+        return undefined;
+    }
+    var left = node.left, right = node.right;
+    var l = isStringLike(left);
+    var r = isStringLike(right);
+    if (l && r) {
+        // They're both strings.
+        // If they're joined by a newline, recommend a template expression instead.
+        // Otherwise ignore. ("a" + "b", probably writing a long newline-less string on many lines.)
+        return containsNewline(left) || containsNewline(right)
+            ? Rule.FAILURE_STRING_MULTILINE
+            : undefined;
+    }
+    else if (!l && !r) {
+        // Watch out for `"a" + b + c`. Parsed as `("a" + b) + c`.
+        return containsAnyStringLiterals(left) ? Rule.FAILURE_STRING : undefined;
+    }
+    else if (l) {
+        // `"x" + y`
+        return !allowSingleConcat ? Rule.FAILURE_STRING : undefined;
+    }
+    else {
+        // `? + "b"`
+        // If LHS consists of only string literals (as in `"a" + "b" + "c"`, allow it.)
+        return !containsOnlyStringLiterals(left) && (!allowSingleConcat || isPlusExpression(left))
+            ? Rule.FAILURE_STRING
+            : undefined;
+    }
+}
+function containsNewline(node) {
+    if (node.kind === ts.SyntaxKind.TemplateExpression) {
+        return node.templateSpans.some(function (_a) {
+            var text = _a.literal.text;
+            return text.includes("\n");
+        });
+    }
+    else {
+        return node.text.includes("\n");
+    }
+}
+function containsOnlyStringLiterals(node) {
+    return (isPlusExpression(node) &&
+        isStringLike(node.right) &&
+        (isStringLike(node.left) || containsAnyStringLiterals(node.left)));
+}
+function containsAnyStringLiterals(node) {
+    return (isPlusExpression(node) &&
+        (isStringLike(node.right) ||
+            isStringLike(node.left) ||
+            containsAnyStringLiterals(node.left)));
+}
+function isPlusExpression(node) {
+    return tsutils_1.isBinaryExpression(node) && node.operatorToken.kind === ts.SyntaxKind.PlusToken;
+}
+function isStringLike(node) {
+    switch (node.kind) {
+        case ts.SyntaxKind.StringLiteral:
+        case ts.SyntaxKind.NoSubstitutionTemplateLiteral:
+        case ts.SyntaxKind.TemplateExpression:
+            return true;
+        default:
+            return false;
+    }
+}
+var templateObject_1;