Initial commit (from f5274cbdce4ae7c9e4b937dcdf95ac70ae436d5f)

node_modules/tslint/lib/rules/preferObjectSpreadRule.js

@@ -0,0 +1,128 @@
+"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 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: "prefer-object-spread",
+        description: "Enforces the use of the ES2018 object spread operator over `Object.assign()` where appropriate.",
+        rationale: "Object spread allows for better type checking and inference.",
+        optionsDescription: "Not configurable.",
+        options: null,
+        optionExamples: [true],
+        type: "functionality",
+        typescriptOnly: false,
+        hasFix: true,
+    };
+    /* tslint:enable:object-literal-sort-keys */
+    Rule.FAILURE_STRING = "Use the object spread operator instead.";
+    Rule.ASSIGNMENT_FAILURE_STRING = "'Object.assign' returns the first argument. Prefer object spread if you want a new object.";
+    return Rule;
+}(Lint.Rules.AbstractRule));
+exports.Rule = Rule;
+function walk(ctx) {
+    return ts.forEachChild(ctx.sourceFile, function cb(node) {
+        if (tsutils_1.isCallExpression(node) &&
+            node.arguments.length !== 0 &&
+            tsutils_1.isPropertyAccessExpression(node.expression) &&
+            node.expression.name.text === "assign" &&
+            tsutils_1.isIdentifier(node.expression.expression) &&
+            node.expression.expression.text === "Object" &&
+            !ts.isFunctionLike(node.arguments[0]) &&
+            // Object.assign(...someArray) cannot be written as object spread
+            !node.arguments.some(tsutils_1.isSpreadElement) &&
+            /**
+             * @TODO
+             * Remove !node.arguments.some(isThisKeyword) when typescript get's
+             * support for spread types.
+             * PR: https://github.com/Microsoft/TypeScript/issues/10727
+             */
+            !node.arguments.some(isThisKeyword)) {
+            if (node.arguments[0].kind === ts.SyntaxKind.ObjectLiteralExpression) {
+                ctx.addFailureAtNode(node, Rule.FAILURE_STRING, createFix(node, ctx.sourceFile));
+            }
+            else if (tsutils_1.isExpressionValueUsed(node) &&
+                !tsutils_1.hasSideEffects(node.arguments[0], 2 /* Constructor */)) {
+                ctx.addFailureAtNode(node, Rule.ASSIGNMENT_FAILURE_STRING, createFix(node, ctx.sourceFile));
+            }
+        }
+        return ts.forEachChild(node, cb);
+    });
+}
+function createFix(node, sourceFile) {
+    var args = node.arguments;
+    var objectNeedsParens = node.parent.kind === ts.SyntaxKind.ArrowFunction;
+    var fix = [
+        Lint.Replacement.replaceFromTo(node.getStart(sourceFile), args[0].getStart(sourceFile), (objectNeedsParens ? "(" : "") + "{"),
+        new Lint.Replacement(node.end - 1, 1, "}" + (objectNeedsParens ? ")" : "")),
+    ];
+    for (var i = 0; i < args.length; ++i) {
+        var arg = args[i];
+        if (tsutils_1.isObjectLiteralExpression(arg)) {
+            if (arg.properties.length === 0) {
+                var end = arg.end;
+                if (i !== args.length - 1) {
+                    end = args[i + 1].getStart(sourceFile);
+                }
+                else if (args.hasTrailingComma) {
+                    end = args.end;
+                }
+                // remove empty object iteral and the following comma if exists
+                fix.push(Lint.Replacement.deleteFromTo(arg.getStart(sourceFile), end));
+            }
+            else {
+                fix.push(
+                // remove open brace
+                Lint.Replacement.deleteText(arg.getStart(sourceFile), 1), 
+                // remove trailing comma if exists and close brace
+                Lint.Replacement.deleteFromTo(arg.properties[arg.properties.length - 1].end, arg.end));
+            }
+        }
+        else {
+            var parens = needsParens(arg);
+            fix.push(Lint.Replacement.appendText(arg.getStart(sourceFile), parens ? "...(" : "..."));
+            if (parens) {
+                fix.push(Lint.Replacement.appendText(arg.end, ")"));
+            }
+        }
+    }
+    return fix;
+}
+function isThisKeyword(node) {
+    return node.kind === ts.SyntaxKind.ThisKeyword;
+}
+function needsParens(node) {
+    switch (node.kind) {
+        case ts.SyntaxKind.ConditionalExpression:
+        case ts.SyntaxKind.BinaryExpression:
+            return true;
+        default:
+            return false;
+    }
+}