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node_modules/tslint/lib/rules/strictComparisonsRule.js

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+"use strict";
+/**
+ * @license
+ * Copyright 2019 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 _a, _b, _c;
+var tsutils_1 = require("tsutils");
+var ts = require("typescript");
+var Lint = require("../index");
+var strictComparisons_examples_1 = require("./code-examples/strictComparisons.examples");
+var OPTION_ALLOW_OBJECT_EQUAL_COMPARISON = "allow-object-equal-comparison";
+var OPTION_ALLOW_STRING_ORDER_COMPARISON = "allow-string-order-comparison";
+var typeNames = (_a = {},
+    _a[0 /* Any */] = "any",
+    _a[1 /* Number */] = "number",
+    _a[2 /* Enum */] = "enum",
+    _a[3 /* String */] = "string",
+    _a[4 /* Boolean */] = "boolean",
+    _a[5 /* Null */] = "null",
+    _a[6 /* Undefined */] = "undefined",
+    _a[7 /* Object */] = "object",
+    _a);
+var Rule = /** @class */ (function (_super) {
+    tslib_1.__extends(Rule, _super);
+    function Rule() {
+        return _super !== null && _super.apply(this, arguments) || this;
+    }
+    /* tslint:enable:object-literal-sort-keys */
+    Rule.INVALID_TYPES = function (types1, types2) {
+        var types1String = types1.map(function (type) { return typeNames[type]; }).join(" | ");
+        var types2String = types2.map(function (type) { return typeNames[type]; }).join(" | ");
+        return "Cannot compare type '" + types1String + "' to type '" + types2String + "'.";
+    };
+    Rule.INVALID_TYPE_FOR_OPERATOR = function (type, comparator) {
+        return "Cannot use '" + comparator + "' comparator for type '" + typeNames[type] + "'.";
+    };
+    Rule.prototype.applyWithProgram = function (sourceFile, program) {
+        return this.applyWithFunction(sourceFile, walk, this.getRuleOptions(), program);
+    };
+    Rule.prototype.getRuleOptions = function () {
+        if (this.ruleArguments[0] === undefined) {
+            return {};
+        }
+        else {
+            return this.ruleArguments[0];
+        }
+    };
+    /* tslint:disable:object-literal-sort-keys */
+    Rule.metadata = {
+        ruleName: "strict-comparisons",
+        description: "Only allow comparisons between primitives.",
+        optionsDescription: Lint.Utils.dedent(templateObject_1 || (templateObject_1 = tslib_1.__makeTemplateObject(["\n                One of the following arguments may be optionally provided:\n                * `", "` allows `!=` `==` `!==` `===` comparison between any types.\n                * `", "` allows `>` `<` `>=` `<=` comparison between strings."], ["\n                One of the following arguments may be optionally provided:\n                * \\`", "\\` allows \\`!=\\` \\`==\\` \\`!==\\` \\`===\\` comparison between any types.\n                * \\`", "\\` allows \\`>\\` \\`<\\` \\`>=\\` \\`<=\\` comparison between strings."])), OPTION_ALLOW_OBJECT_EQUAL_COMPARISON, OPTION_ALLOW_STRING_ORDER_COMPARISON),
+        options: {
+            type: "object",
+            properties: (_b = {},
+                _b[OPTION_ALLOW_OBJECT_EQUAL_COMPARISON] = {
+                    type: "boolean",
+                },
+                _b[OPTION_ALLOW_STRING_ORDER_COMPARISON] = {
+                    type: "boolean",
+                },
+                _b),
+        },
+        optionExamples: [
+            true,
+            [
+                true,
+                (_c = {},
+                    _c[OPTION_ALLOW_OBJECT_EQUAL_COMPARISON] = false,
+                    _c[OPTION_ALLOW_STRING_ORDER_COMPARISON] = false,
+                    _c),
+            ],
+        ],
+        rationale: Lint.Utils.dedent(templateObject_2 || (templateObject_2 = tslib_1.__makeTemplateObject(["\n                When using comparison operators to compare objects, they compare references and not values.\n                This is often done accidentally.\n                With this rule, `>`, `>=`, `<`, `<=` operators are only allowed when comparing `numbers`.\n                `===`, `!==` are allowed for `number` `string` and `boolean` types and if one of the\n                operands is `null` or `undefined`.\n            "], ["\n                When using comparison operators to compare objects, they compare references and not values.\n                This is often done accidentally.\n                With this rule, \\`>\\`, \\`>=\\`, \\`<\\`, \\`<=\\` operators are only allowed when comparing \\`numbers\\`.\n                \\`===\\`, \\`!==\\` are allowed for \\`number\\` \\`string\\` and \\`boolean\\` types and if one of the\n                operands is \\`null\\` or \\`undefined\\`.\n            "]))),
+        type: "functionality",
+        typescriptOnly: false,
+        requiresTypeInfo: true,
+        codeExamples: strictComparisons_examples_1.codeExamples,
+    };
+    return Rule;
+}(Lint.Rules.TypedRule));
+exports.Rule = Rule;
+function walk(ctx, program) {
+    var sourceFile = ctx.sourceFile, options = ctx.options;
+    var checker = program.getTypeChecker();
+    return ts.forEachChild(sourceFile, function cb(node) {
+        if (tsutils_1.isBinaryExpression(node) && isComparisonOperator(node)) {
+            var isEquality = isEqualityOperator(node);
+            var leftType = checker.getTypeAtLocation(node.left);
+            var rightType = checker.getTypeAtLocation(node.right);
+            if ((containsNullOrUndefined(leftType) || containsNullOrUndefined(rightType)) &&
+                isEquality) {
+                return;
+            }
+            var leftKinds = getTypes(leftType);
+            var rightKinds = getTypes(rightType);
+            var operandKind = getStrictestComparableType(leftKinds, rightKinds);
+            if (operandKind === undefined) {
+                var failureString = Rule.INVALID_TYPES(leftKinds, rightKinds);
+                ctx.addFailureAtNode(node, failureString);
+            }
+            else {
+                var failureString = Rule.INVALID_TYPE_FOR_OPERATOR(operandKind, node.operatorToken.getText());
+                if (isEquality) {
+                    // Check !=, ==, !==, ===
+                    switch (operandKind) {
+                        case 0 /* Any */:
+                        case 1 /* Number */:
+                        case 2 /* Enum */:
+                        case 3 /* String */:
+                        case 4 /* Boolean */:
+                            break;
+                        case 5 /* Null */:
+                        case 6 /* Undefined */:
+                        case 7 /* Object */:
+                            if (options[OPTION_ALLOW_OBJECT_EQUAL_COMPARISON]) {
+                                break;
+                            }
+                            ctx.addFailureAtNode(node, failureString);
+                            break;
+                        default:
+                            ctx.addFailureAtNode(node, failureString);
+                    }
+                }
+                else {
+                    // Check >, <, >=, <=
+                    switch (operandKind) {
+                        case 0 /* Any */:
+                        case 1 /* Number */:
+                            break;
+                        case 3 /* String */:
+                            if (options[OPTION_ALLOW_STRING_ORDER_COMPARISON]) {
+                                break;
+                            }
+                            ctx.addFailureAtNode(node, failureString);
+                            break;
+                        default:
+                            ctx.addFailureAtNode(node, failureString);
+                    }
+                }
+            }
+        }
+        return ts.forEachChild(node, cb);
+    });
+}
+function containsNullOrUndefined(type) {
+    return (type.intrinsicName === "null" ||
+        type.intrinsicName === "undefined");
+}
+function getTypes(types) {
+    // Compatibility for TypeScript pre-2.4, which used EnumLiteralType instead of LiteralType
+    var baseType = types.baseType;
+    return tsutils_1.isUnionType(types)
+        ? Array.from(new Set(types.types.map(getKind)))
+        : tsutils_1.isTypeFlagSet(types, ts.TypeFlags.EnumLiteral) && typeof baseType !== "undefined"
+            ? [getKind(baseType)]
+            : [getKind(types)];
+}
+function getStrictestComparableType(typesLeft, typesRight) {
+    var overlappingTypes = typesLeft.filter(function (type) { return typesRight.indexOf(type) >= 0; });
+    if (overlappingTypes.length > 0) {
+        return getStrictestKind(overlappingTypes);
+    }
+    else {
+        // In case one of the types is "any", get the strictest type of the other array
+        if (arrayContainsKind(typesLeft, [0 /* Any */])) {
+            return getStrictestKind(typesRight);
+        }
+        if (arrayContainsKind(typesRight, [0 /* Any */])) {
+            return getStrictestKind(typesLeft);
+        }
+        // In case one array contains NullOrUndefined and the other an Object, return Object
+        if ((arrayContainsKind(typesLeft, [5 /* Null */, 6 /* Undefined */]) &&
+            arrayContainsKind(typesRight, [7 /* Object */])) ||
+            (arrayContainsKind(typesRight, [5 /* Null */, 6 /* Undefined */]) &&
+                arrayContainsKind(typesLeft, [7 /* Object */]))) {
+            return 7 /* Object */;
+        }
+        return undefined;
+    }
+}
+function arrayContainsKind(types, typeToCheck) {
+    return types.some(function (type) { return typeToCheck.indexOf(type) >= 0; });
+}
+function getStrictestKind(types) {
+    // tslint:disable-next-line:no-unsafe-any
+    return Math.max.apply(Math, types);
+}
+function isComparisonOperator(node) {
+    switch (node.operatorToken.kind) {
+        case ts.SyntaxKind.LessThanToken:
+        case ts.SyntaxKind.GreaterThanToken:
+        case ts.SyntaxKind.LessThanEqualsToken:
+        case ts.SyntaxKind.GreaterThanEqualsToken:
+        case ts.SyntaxKind.EqualsEqualsToken:
+        case ts.SyntaxKind.ExclamationEqualsToken:
+        case ts.SyntaxKind.EqualsEqualsEqualsToken:
+        case ts.SyntaxKind.ExclamationEqualsEqualsToken:
+            return true;
+        default:
+            return false;
+    }
+}
+function isEqualityOperator(node) {
+    switch (node.operatorToken.kind) {
+        case ts.SyntaxKind.EqualsEqualsToken:
+        case ts.SyntaxKind.ExclamationEqualsToken:
+        case ts.SyntaxKind.EqualsEqualsEqualsToken:
+        case ts.SyntaxKind.ExclamationEqualsEqualsToken:
+            return true;
+        default:
+            return false;
+    }
+}
+function getKind(type) {
+    // tslint:disable:no-bitwise
+    if (is(ts.TypeFlags.String | ts.TypeFlags.StringLiteral)) {
+        return 3 /* String */;
+    }
+    else if (is(ts.TypeFlags.Number | ts.TypeFlags.NumberLiteral)) {
+        return 1 /* Number */;
+    }
+    else if (is(ts.TypeFlags.BooleanLike)) {
+        return 4 /* Boolean */;
+    }
+    else if (is(ts.TypeFlags.Null)) {
+        return 5 /* Null */;
+    }
+    else if (is(ts.TypeFlags.Undefined)) {
+        return 6 /* Undefined */;
+    }
+    else if (is(ts.TypeFlags.Any)) {
+        return 0 /* Any */;
+    }
+    else {
+        return 7 /* Object */;
+    }
+    // tslint:enable:no-bitwise
+    function is(flags) {
+        return tsutils_1.isTypeFlagSet(type, flags);
+    }
+}
+var templateObject_1, templateObject_2;