--- /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 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 compilerOptions = program.getCompilerOptions();
+ var strictChecksEnabled = !!compilerOptions.strict;
+ var strictNullChecksEnabled = compilerOptions.strictNullChecks === true;
+ var strictNullChecksNotDisabled = compilerOptions.strictNullChecks !== false;
+ return this.applyWithWalker(new Walker(sourceFile, this.ruleName, this.ruleArguments, program.getTypeChecker(), strictNullChecksEnabled || (strictChecksEnabled && strictNullChecksNotDisabled)));
+ };
+ /* tslint:disable:object-literal-sort-keys */
+ Rule.metadata = {
+ ruleName: "no-unnecessary-type-assertion",
+ description: "Warns if a type assertion does not change the type of an expression.",
+ options: {
+ type: "list",
+ listType: {
+ type: "array",
+ items: { type: "string" },
+ },
+ },
+ optionsDescription: "A list of whitelisted assertion types to ignore",
+ type: "typescript",
+ hasFix: true,
+ typescriptOnly: true,
+ requiresTypeInfo: true,
+ };
+ /* tslint:enable:object-literal-sort-keys */
+ Rule.FAILURE_STRING = "This assertion is unnecessary since it does not change the type of the expression.";
+ return Rule;
+}(Lint.Rules.TypedRule));
+exports.Rule = Rule;
+var Walker = /** @class */ (function (_super) {
+ tslib_1.__extends(Walker, _super);
+ function Walker(sourceFile, ruleName, options, checker, strictNullChecks) {
+ var _this = _super.call(this, sourceFile, ruleName, options) || this;
+ _this.checker = checker;
+ _this.strictNullChecks = strictNullChecks;
+ return _this;
+ }
+ Walker.prototype.walk = function (sourceFile) {
+ var _this = this;
+ var cb = function (node) {
+ switch (node.kind) {
+ case ts.SyntaxKind.NonNullExpression:
+ if (_this.strictNullChecks) {
+ _this.checkNonNullAssertion(node);
+ }
+ break;
+ case ts.SyntaxKind.TypeAssertionExpression:
+ case ts.SyntaxKind.AsExpression:
+ _this.verifyCast(node);
+ }
+ return ts.forEachChild(node, cb);
+ };
+ return ts.forEachChild(sourceFile, cb);
+ };
+ Walker.prototype.checkNonNullAssertion = function (node) {
+ var type = this.checker.getTypeAtLocation(node.expression);
+ if (type === this.checker.getNonNullableType(type)) {
+ this.addFailureAtNode(node, Rule.FAILURE_STRING, Lint.Replacement.deleteFromTo(node.expression.end, node.end));
+ }
+ };
+ Walker.prototype.verifyCast = function (node) {
+ if (this.options.indexOf(node.type.getText(this.sourceFile)) !== -1) {
+ return;
+ }
+ var castType = this.checker.getTypeAtLocation(node);
+ if (tsutils_1.isTypeFlagSet(castType, ts.TypeFlags.Literal) ||
+ (tsutils_1.isObjectType(castType) &&
+ (tsutils_1.isObjectFlagSet(castType, ts.ObjectFlags.Tuple) || couldBeTupleType(castType)))) {
+ // It's not always safe to remove a cast to a literal type or tuple
+ // type, as those types are sometimes widened without the cast.
+ return;
+ }
+ var uncastType = this.checker.getTypeAtLocation(node.expression);
+ if (uncastType === castType) {
+ this.addFailureAtNode(node, Rule.FAILURE_STRING, node.kind === ts.SyntaxKind.TypeAssertionExpression
+ ? Lint.Replacement.deleteFromTo(node.getStart(), node.expression.getStart())
+ : Lint.Replacement.deleteFromTo(node.expression.end, node.end));
+ }
+ };
+ return Walker;
+}(Lint.AbstractWalker));
+/**
+ * Sometimes tuple types don't have ObjectFlags.Tuple set, like when they're being matched against an inferred type.
+ * So, in addition, check if there are integer properties 0..n and no other numeric keys
+ */
+function couldBeTupleType(type) {
+ var properties = type.getProperties();
+ if (properties.length === 0) {
+ return false;
+ }
+ var i = 0;
+ for (; i < properties.length; ++i) {
+ var name = properties[i].name;
+ if (String(i) !== name) {
+ if (i === 0) {
+ // if there are no integer properties, this is not a tuple
+ return false;
+ }
+ break;
+ }
+ }
+ for (; i < properties.length; ++i) {
+ if (String(+properties[i].name) === properties[i].name) {
+ return false; // if there are any other numeric properties, this is not a tuple
+ }
+ }
+ return true;
+}
projects / dotfiles / .git / blobdiff