--- /dev/null
+"use strict";
+/**
+ * @license
+ * Copyright 2018 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 OPTION_ALLOW_NULL_UNION = "allow-null-union";
+var OPTION_ALLOW_UNDEFINED_UNION = "allow-undefined-union";
+var OPTION_ALLOW_STRING = "allow-string";
+var OPTION_ALLOW_ENUM = "allow-enum";
+var OPTION_ALLOW_NUMBER = "allow-number";
+var OPTION_ALLOW_MIX = "allow-mix";
+var OPTION_ALLOW_BOOLEAN_OR_UNDEFINED = "allow-boolean-or-undefined";
+var OPTION_IGNORE_RHS = "ignore-rhs";
+// tslint:disable object-literal-sort-keys no-bitwise
+var Rule = /** @class */ (function (_super) {
+ tslib_1.__extends(Rule, _super);
+ function Rule() {
+ return _super !== null && _super.apply(this, arguments) || this;
+ }
+ Rule.prototype.applyWithProgram = function (sourceFile, program) {
+ var options = parseOptions(this.ruleArguments, Lint.isStrictNullChecksEnabled(program.getCompilerOptions()));
+ return this.applyWithFunction(sourceFile, walk, options, program.getTypeChecker());
+ };
+ Rule.metadata = {
+ ruleName: "strict-boolean-expressions",
+ description: Lint.Utils.dedent(templateObject_1 || (templateObject_1 = tslib_1.__makeTemplateObject(["\n Restricts the types allowed in boolean expressions. By default only booleans are allowed.\n\n The following nodes are checked:\n\n * Arguments to the `!`, `&&`, and `||` operators\n * The condition in a conditional expression (`cond ? x : y`)\n * Conditions for `if`, `for`, `while`, and `do-while` statements."], ["\n Restricts the types allowed in boolean expressions. By default only booleans are allowed.\n\n The following nodes are checked:\n\n * Arguments to the \\`!\\`, \\`&&\\`, and \\`||\\` operators\n * The condition in a conditional expression (\\`cond ? x : y\\`)\n * Conditions for \\`if\\`, \\`for\\`, \\`while\\`, and \\`do-while\\` statements."]))),
+ optionsDescription: Lint.Utils.dedent(templateObject_2 || (templateObject_2 = tslib_1.__makeTemplateObject(["\n These options may be provided:\n\n * `", "` allows union types containing `null`.\n - It does *not* allow `null` itself.\n - Without the '--strictNullChecks' compiler option, this will allow anything other than a string, number, or enum.\n * `", "` allows union types containing `undefined`.\n - It does *not* allow `undefined` itself.\n - Without the '--strictNullChecks' compiler option, this will allow anything other than a string, number, or enum.\n * `", "` allows strings.\n - It does *not* allow unions containing `string`.\n - It does *not* allow string literal types.\n * `", "` allows enums.\n - It does *not* allow unions containing `enum`.\n * `", "` allows numbers.\n - It does *not* allow unions containing `number`.\n - It does *not* allow enums or number literal types.\n * `", "` allows multiple of the above to appear together.\n - For example, `string | number` or `RegExp | null | undefined` would normally not be allowed.\n - A type like `\"foo\" | \"bar\" | undefined` is always allowed, because it has only one way to be false.\n * `", "` allows `boolean | undefined`.\n - Also allows `true | false | undefined`.\n - Does not allow `false | undefined`.\n - This option is a subset of `", "`, so you don't need to enable both options at the same time.\n * `", "` ignores the right-hand operand of `&&` and `||`.\n "], ["\n These options may be provided:\n\n * \\`", "\\` allows union types containing \\`null\\`.\n - It does *not* allow \\`null\\` itself.\n - Without the '--strictNullChecks' compiler option, this will allow anything other than a string, number, or enum.\n * \\`", "\\` allows union types containing \\`undefined\\`.\n - It does *not* allow \\`undefined\\` itself.\n - Without the '--strictNullChecks' compiler option, this will allow anything other than a string, number, or enum.\n * \\`", "\\` allows strings.\n - It does *not* allow unions containing \\`string\\`.\n - It does *not* allow string literal types.\n * \\`", "\\` allows enums.\n - It does *not* allow unions containing \\`enum\\`.\n * \\`", "\\` allows numbers.\n - It does *not* allow unions containing \\`number\\`.\n - It does *not* allow enums or number literal types.\n * \\`", "\\` allows multiple of the above to appear together.\n - For example, \\`string | number\\` or \\`RegExp | null | undefined\\` would normally not be allowed.\n - A type like \\`\"foo\" | \"bar\" | undefined\\` is always allowed, because it has only one way to be false.\n * \\`", "\\` allows \\`boolean | undefined\\`.\n - Also allows \\`true | false | undefined\\`.\n - Does not allow \\`false | undefined\\`.\n - This option is a subset of \\`", "\\`, so you don't need to enable both options at the same time.\n * \\`", "\\` ignores the right-hand operand of \\`&&\\` and \\`||\\`.\n "])), OPTION_ALLOW_NULL_UNION, OPTION_ALLOW_UNDEFINED_UNION, OPTION_ALLOW_STRING, OPTION_ALLOW_ENUM, OPTION_ALLOW_NUMBER, OPTION_ALLOW_MIX, OPTION_ALLOW_BOOLEAN_OR_UNDEFINED, OPTION_ALLOW_UNDEFINED_UNION, OPTION_IGNORE_RHS),
+ options: {
+ type: "array",
+ items: {
+ type: "string",
+ enum: [
+ OPTION_ALLOW_NULL_UNION,
+ OPTION_ALLOW_UNDEFINED_UNION,
+ OPTION_ALLOW_STRING,
+ OPTION_ALLOW_ENUM,
+ OPTION_ALLOW_NUMBER,
+ OPTION_ALLOW_BOOLEAN_OR_UNDEFINED,
+ OPTION_IGNORE_RHS,
+ ],
+ },
+ minLength: 0,
+ maxLength: 7,
+ },
+ optionExamples: [
+ true,
+ [
+ true,
+ OPTION_ALLOW_NULL_UNION,
+ OPTION_ALLOW_UNDEFINED_UNION,
+ OPTION_ALLOW_STRING,
+ OPTION_ALLOW_ENUM,
+ OPTION_ALLOW_NUMBER,
+ ],
+ [true, OPTION_ALLOW_BOOLEAN_OR_UNDEFINED],
+ ],
+ type: "functionality",
+ typescriptOnly: true,
+ requiresTypeInfo: true,
+ };
+ return Rule;
+}(Lint.Rules.TypedRule));
+exports.Rule = Rule;
+function parseOptions(ruleArguments, strictNullChecks) {
+ return {
+ strictNullChecks: strictNullChecks,
+ allowNullUnion: has(OPTION_ALLOW_NULL_UNION),
+ allowUndefinedUnion: has(OPTION_ALLOW_UNDEFINED_UNION),
+ allowString: has(OPTION_ALLOW_STRING),
+ allowEnum: has(OPTION_ALLOW_ENUM),
+ allowNumber: has(OPTION_ALLOW_NUMBER),
+ allowMix: has(OPTION_ALLOW_MIX),
+ allowBooleanOrUndefined: has(OPTION_ALLOW_BOOLEAN_OR_UNDEFINED),
+ ignoreRhs: has(OPTION_IGNORE_RHS),
+ };
+ function has(name) {
+ return ruleArguments.indexOf(name) !== -1;
+ }
+}
+function walk(ctx, checker) {
+ var sourceFile = ctx.sourceFile, options = ctx.options;
+ ts.forEachChild(sourceFile, function cb(node) {
+ switch (node.kind) {
+ case ts.SyntaxKind.BinaryExpression: {
+ var b = node;
+ if (binaryBooleanExpressionKind(b) !== undefined) {
+ var left = b.left, right = b.right;
+ // If ignore-rhs is off, we don't have to analyze a boolean binary expression
+ // on the left side because it will be checked well enough on its own. However,
+ // if ignore-rhs is on, we have to analyze the overall result of the left
+ // side no matter what, because its right side might not follow the rules.
+ if (!isBooleanBinaryExpression(left)) {
+ checkExpression(left, b);
+ }
+ // If ignore-rhs is on, we don't have to analyze the right hand side
+ // We also don't have to analyze the right hand side if it is also a
+ // boolean binary expression; its own inner check is sufficient.
+ if (!(options.ignoreRhs || isBooleanBinaryExpression(right))) {
+ checkExpression(right, b);
+ }
+ }
+ break;
+ }
+ case ts.SyntaxKind.PrefixUnaryExpression: {
+ var _a = node, operator = _a.operator, operand = _a.operand;
+ if (operator === ts.SyntaxKind.ExclamationToken) {
+ checkExpression(operand, node);
+ }
+ break;
+ }
+ case ts.SyntaxKind.IfStatement:
+ case ts.SyntaxKind.WhileStatement:
+ case ts.SyntaxKind.DoStatement: {
+ var c = node;
+ // If it's a boolean binary expression, we'll check it when recursing.
+ if (!isBooleanBinaryExpression(c.expression)) {
+ checkExpression(c.expression, c);
+ }
+ break;
+ }
+ case ts.SyntaxKind.ConditionalExpression:
+ checkExpression(node.condition, node);
+ break;
+ case ts.SyntaxKind.ForStatement: {
+ var condition = node.condition;
+ if (condition !== undefined) {
+ checkExpression(condition, node);
+ }
+ }
+ }
+ return ts.forEachChild(node, cb);
+ });
+ function checkExpression(node, location) {
+ var type = checker.getTypeAtLocation(node);
+ var failure = getTypeFailure(type, options);
+ if (failure !== undefined) {
+ if (failure === 0 /* AlwaysTruthy */ &&
+ !options.strictNullChecks &&
+ (options.allowNullUnion || options.allowUndefinedUnion)) {
+ // OK; It might be null/undefined.
+ return;
+ }
+ ctx.addFailureAtNode(node, showFailure(location, failure, isUnionType(type), options));
+ }
+ }
+}
+function getTypeFailure(type, options) {
+ if (isUnionType(type)) {
+ return handleUnion(type, options);
+ }
+ var kind = getKind(type);
+ var failure = failureForKind(kind, /*isInUnion*/ false, options);
+ if (failure !== undefined) {
+ return failure;
+ }
+ switch (triState(kind)) {
+ case true:
+ // Allow 'any'. Allow 'true' itself, but not any other always-truthy type.
+ return tsutils_1.isTypeFlagSet(type, ts.TypeFlags.Any | ts.TypeFlags.BooleanLiteral)
+ ? undefined
+ : 0 /* AlwaysTruthy */;
+ case false:
+ // Allow 'false' itself, but not any other always-falsy type
+ return tsutils_1.isTypeFlagSet(type, ts.TypeFlags.BooleanLiteral)
+ ? undefined
+ : 1 /* AlwaysFalsy */;
+ case undefined:
+ return undefined;
+ }
+}
+function isBooleanUndefined(type) {
+ var isTruthy = false;
+ for (var _i = 0, _a = type.types; _i < _a.length; _i++) {
+ var ty = _a[_i];
+ if (tsutils_1.isTypeFlagSet(ty, ts.TypeFlags.Boolean)) {
+ isTruthy = true;
+ }
+ else if (tsutils_1.isTypeFlagSet(ty, ts.TypeFlags.BooleanLiteral)) {
+ isTruthy = isTruthy || ty.intrinsicName === "true";
+ // tslint:disable-next-line:no-bitwise
+ }
+ else if (!tsutils_1.isTypeFlagSet(ty, ts.TypeFlags.Void | ts.TypeFlags.Undefined)) {
+ return undefined;
+ }
+ }
+ return isTruthy;
+}
+function handleUnion(type, options) {
+ if (options.allowBooleanOrUndefined) {
+ switch (isBooleanUndefined(type)) {
+ case true:
+ return undefined;
+ case false:
+ return 1 /* AlwaysFalsy */;
+ }
+ }
+ // Tracks whether it's possibly truthy.
+ var anyTruthy = false;
+ // Counts falsy kinds to see if there's a mix. Also tracks whether it's possibly falsy.
+ var seenFalsy = 0;
+ for (var _i = 0, _a = type.types; _i < _a.length; _i++) {
+ var ty = _a[_i];
+ var kind = getKind(ty);
+ var failure = failureForKind(kind, /*isInUnion*/ true, options);
+ if (failure !== undefined) {
+ return failure;
+ }
+ switch (triState(kind)) {
+ case true:
+ anyTruthy = true;
+ break;
+ case false:
+ seenFalsy++;
+ break;
+ default:
+ anyTruthy = true;
+ seenFalsy++;
+ }
+ }
+ return seenFalsy === 0
+ ? 0 /* AlwaysTruthy */
+ : !anyTruthy
+ ? 1 /* AlwaysFalsy */
+ : !options.allowMix && seenFalsy > 1
+ ? 7 /* Mixes */
+ : undefined;
+}
+/** Fails if a kind of falsiness is not allowed. */
+function failureForKind(kind, isInUnion, options) {
+ switch (kind) {
+ case 0 /* String */:
+ case 1 /* FalseStringLiteral */:
+ return options.allowString ? undefined : 2 /* String */;
+ case 2 /* Number */:
+ case 3 /* FalseNumberLiteral */:
+ return options.allowNumber ? undefined : 3 /* Number */;
+ case 8 /* Enum */:
+ return options.allowEnum ? undefined : 6 /* Enum */;
+ case 6 /* Null */:
+ return isInUnion && !options.allowNullUnion ? 4 /* Null */ : undefined;
+ case 7 /* Undefined */:
+ return isInUnion && !options.allowUndefinedUnion ? 5 /* Undefined */ : undefined;
+ default:
+ return undefined;
+ }
+}
+/** Divides a type into always true, always false, or unknown. */
+function triState(kind) {
+ switch (kind) {
+ case 0 /* String */:
+ case 2 /* Number */:
+ case 4 /* Boolean */:
+ case 8 /* Enum */:
+ return undefined;
+ case 6 /* Null */:
+ case 7 /* Undefined */:
+ case 3 /* FalseNumberLiteral */:
+ case 1 /* FalseStringLiteral */:
+ case 5 /* FalseBooleanLiteral */:
+ return false;
+ case 9 /* AlwaysTruthy */:
+ return true;
+ }
+}
+function getKind(type) {
+ return is(ts.TypeFlags.String)
+ ? 0 /* String */
+ : is(ts.TypeFlags.Number)
+ ? 2 /* Number */
+ : is(ts.TypeFlags.Boolean)
+ ? 4 /* Boolean */
+ : is(ts.TypeFlags.Null)
+ ? 6 /* Null */
+ : is(ts.TypeFlags.Undefined | ts.TypeFlags.Void)
+ ? 7 /* Undefined */
+ : is(ts.TypeFlags.EnumLike)
+ ? 8 /* Enum */
+ : is(ts.TypeFlags.NumberLiteral)
+ ? numberLiteralIsZero(type)
+ ? 3 /* FalseNumberLiteral */
+ : 9 /* AlwaysTruthy */
+ : is(ts.TypeFlags.StringLiteral)
+ ? stringLiteralIsEmpty(type)
+ ? 1 /* FalseStringLiteral */
+ : 9 /* AlwaysTruthy */
+ : is(ts.TypeFlags.BooleanLiteral)
+ ? type.intrinsicName === "true"
+ ? 9 /* AlwaysTruthy */
+ : 5 /* FalseBooleanLiteral */
+ : 9 /* AlwaysTruthy */;
+ function is(flags) {
+ return tsutils_1.isTypeFlagSet(type, flags);
+ }
+}
+function numberLiteralIsZero(type) {
+ // for compatibility with typescript@<2.4.0
+ return type.value !== undefined ? type.value === 0 : type.text === "0";
+}
+function stringLiteralIsEmpty(type) {
+ // for compatibility with typescript@<2.4.0
+ return (type.value !== undefined ? type.value : type.text) === "";
+}
+/** Matches `&&` and `||` operators. */
+function isBooleanBinaryExpression(node) {
+ return (node.kind === ts.SyntaxKind.BinaryExpression &&
+ binaryBooleanExpressionKind(node) !== undefined);
+}
+function binaryBooleanExpressionKind(node) {
+ switch (node.operatorToken.kind) {
+ case ts.SyntaxKind.AmpersandAmpersandToken:
+ return "&&";
+ case ts.SyntaxKind.BarBarToken:
+ return "||";
+ default:
+ return undefined;
+ }
+}
+function stringOr(parts) {
+ switch (parts.length) {
+ case 1:
+ return parts[0];
+ case 2:
+ return parts[0] + " or " + parts[1];
+ default:
+ var res = "";
+ for (var i = 0; i < parts.length - 1; i++) {
+ res += parts[i] + ", ";
+ }
+ return res + "or " + parts[parts.length - 1];
+ }
+}
+function isUnionType(type) {
+ return tsutils_1.isTypeFlagSet(type, ts.TypeFlags.Union) && !tsutils_1.isTypeFlagSet(type, ts.TypeFlags.Enum);
+}
+function showLocation(n) {
+ switch (n.kind) {
+ case ts.SyntaxKind.PrefixUnaryExpression:
+ return "operand for the '!' operator";
+ case ts.SyntaxKind.ConditionalExpression:
+ return "condition";
+ case ts.SyntaxKind.ForStatement:
+ return "'for' condition";
+ case ts.SyntaxKind.IfStatement:
+ return "'if' condition";
+ case ts.SyntaxKind.WhileStatement:
+ return "'while' condition";
+ case ts.SyntaxKind.DoStatement:
+ return "'do-while' condition";
+ case ts.SyntaxKind.BinaryExpression:
+ return "operand for the '" + binaryBooleanExpressionKind(n) + "' operator";
+ }
+}
+function showFailure(location, ty, unionType, options) {
+ var expectedTypes = showExpectedTypes(options);
+ var expected = expectedTypes.length === 1
+ ? "Only " + expectedTypes[0] + "s are allowed"
+ : "Allowed types are " + stringOr(expectedTypes);
+ var tyFail = showTypeFailure(ty, unionType, options.strictNullChecks);
+ return "This type is not allowed in the " + showLocation(location) + " because it " + tyFail + ". " + expected + ".";
+}
+function showExpectedTypes(options) {
+ var parts = ["boolean"];
+ if (options.allowNullUnion) {
+ parts.push("null-union");
+ }
+ if (options.allowUndefinedUnion) {
+ parts.push("undefined-union");
+ }
+ if (options.allowString) {
+ parts.push("string");
+ }
+ if (options.allowEnum) {
+ parts.push("enum");
+ }
+ if (options.allowNumber) {
+ parts.push("number");
+ }
+ if (options.allowBooleanOrUndefined) {
+ parts.push("boolean-or-undefined");
+ }
+ return parts;
+}
+function showTypeFailure(ty, unionType, strictNullChecks) {
+ var is = unionType ? "could be" : "is";
+ switch (ty) {
+ case 0 /* AlwaysTruthy */:
+ return strictNullChecks
+ ? "is always truthy"
+ : "is always truthy. It may be null/undefined, but neither " +
+ ("'" + OPTION_ALLOW_NULL_UNION + "' nor '" + OPTION_ALLOW_UNDEFINED_UNION + "' is set");
+ case 1 /* AlwaysFalsy */:
+ return "is always falsy";
+ case 2 /* String */:
+ return is + " a string";
+ case 3 /* Number */:
+ return is + " a number";
+ case 4 /* Null */:
+ return is + " null";
+ case 5 /* Undefined */:
+ return is + " undefined";
+ case 6 /* Enum */:
+ return is + " an enum";
+ case 7 /* Mixes */:
+ return "unions more than one truthy/falsy type";
+ }
+}
+var templateObject_1, templateObject_2;
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