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"use strict";
/**
* @license
* Copyright 2014 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 });
exports.Rule = void 0;
var tslib_1 = require("tslib");
var tsutils_1 = require("tsutils");
var ts = require("typescript");
var Lint = require("../index");
var ALLOW_FAST_NULL_CHECKS = "allow-fast-null-checks";
var ALLOW_NEW = "allow-new";
var ALLOW_TAGGED_TEMPLATE = "allow-tagged-template";
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, {
allowFastNullChecks: this.ruleArguments.indexOf(ALLOW_FAST_NULL_CHECKS) !== -1,
allowNew: this.ruleArguments.indexOf(ALLOW_NEW) !== -1,
allowTaggedTemplate: this.ruleArguments.indexOf(ALLOW_TAGGED_TEMPLATE) !== -1,
});
};
/* tslint:disable:object-literal-sort-keys */
Rule.metadata = {
ruleName: "no-unused-expression",
description: "Disallows unused expression statements.",
descriptionDetails: Lint.Utils.dedent(templateObject_1 || (templateObject_1 = tslib_1.__makeTemplateObject(["\n Unused expressions are expression statements which are not assignments or function calls\n (and thus usually no-ops)."], ["\n Unused expressions are expression statements which are not assignments or function calls\n (and thus usually no-ops)."]))),
rationale: Lint.Utils.dedent(templateObject_2 || (templateObject_2 = tslib_1.__makeTemplateObject(["\n Detects potential errors where an assignment or function call was intended."], ["\n Detects potential errors where an assignment or function call was intended."]))),
optionsDescription: Lint.Utils.dedent(templateObject_3 || (templateObject_3 = tslib_1.__makeTemplateObject(["\n Three arguments may be optionally provided:\n\n * `", "` allows to use logical operators to perform fast null checks and perform\n method or function calls for side effects (e.g. `e && e.preventDefault()`).\n * `", "` allows 'new' expressions for side effects (e.g. `new ModifyGlobalState();`.\n * `", "` allows tagged templates for side effects (e.g. `this.add\\`foo\\`;`."], ["\n Three arguments may be optionally provided:\n\n * \\`", "\\` allows to use logical operators to perform fast null checks and perform\n method or function calls for side effects (e.g. \\`e && e.preventDefault()\\`).\n * \\`", "\\` allows 'new' expressions for side effects (e.g. \\`new ModifyGlobalState();\\`.\n * \\`", "\\` allows tagged templates for side effects (e.g. \\`this.add\\\\\\`foo\\\\\\`;\\`."])), ALLOW_FAST_NULL_CHECKS, ALLOW_NEW, ALLOW_TAGGED_TEMPLATE),
options: {
type: "array",
items: {
type: "string",
enum: [ALLOW_FAST_NULL_CHECKS, ALLOW_NEW, ALLOW_TAGGED_TEMPLATE],
},
minLength: 0,
maxLength: 3,
},
optionExamples: [true, [true, ALLOW_FAST_NULL_CHECKS]],
type: "functionality",
typescriptOnly: false,
};
/* tslint:enable:object-literal-sort-keys */
Rule.FAILURE_STRING = "unused expression, expected an assignment or function call";
return Rule;
}(Lint.Rules.AbstractRule));
exports.Rule = Rule;
function walk(ctx) {
var checking = false;
var allowFastNullChecks = true;
return ts.forEachChild(ctx.sourceFile, cb);
function cb(node) {
if (checking) {
if (tsutils_1.isParenthesizedExpression(node) || tsutils_1.isVoidExpression(node)) {
return cb(node.expression);
}
else if (tsutils_1.isConditionalExpression(node)) {
noCheck(node.condition, cb);
return both(node.whenTrue, node.whenFalse);
}
else if (tsutils_1.isBinaryExpression(node)) {
switch (node.operatorToken.kind) {
case ts.SyntaxKind.CommaToken:
if (isIndirectEval(node)) {
return false;
}
return both(node.left, node.right);
case ts.SyntaxKind.AmpersandAmpersandToken:
case ts.SyntaxKind.BarBarToken:
if (allowFastNullChecks) {
noCheck(node.left, cb);
return cb(node.right);
}
}
}
noCheck(node, forEachChild);
return isUnusedExpression(node, ctx.options);
}
if (tsutils_1.isExpressionStatement(node)) {
allowFastNullChecks = ctx.options.allowFastNullChecks;
if (!isDirective(node)) {
check(node.expression, node);
}
allowFastNullChecks = true;
return false;
}
else if (tsutils_1.isVoidExpression(node)) {
// allow `void 0` and `void(0)`
if (!isLiteralZero(tsutils_1.isParenthesizedExpression(node.expression)
? node.expression.expression
: node.expression)) {
check(node.expression);
}
return false;
}
else if (tsutils_1.isBinaryExpression(node) &&
node.operatorToken.kind === ts.SyntaxKind.CommaToken &&
!isIndirectEval(node)) {
check(node.left);
return cb(node.right);
}
return ts.forEachChild(node, cb);
}
function forEachChild(node) {
return ts.forEachChild(node, cb);
}
function check(node, failNode) {
checking = true;
if (cb(node)) {
ctx.addFailureAtNode(failNode === undefined ? node : failNode, Rule.FAILURE_STRING);
}
checking = false;
}
function noCheck(node, callback) {
var old = allowFastNullChecks;
checking = false;
allowFastNullChecks = true;
callback(node);
allowFastNullChecks = old;
checking = true;
}
function both(one, two) {
if (cb(one)) {
if (cb(two)) {
return true;
}
else {
ctx.addFailureAtNode(one, Rule.FAILURE_STRING);
}
}
else if (cb(two)) {
ctx.addFailureAtNode(two, Rule.FAILURE_STRING);
}
return false;
}
}
function isUnusedExpression(node, options) {
switch (node.kind) {
case ts.SyntaxKind.CallExpression:
case ts.SyntaxKind.YieldExpression:
case ts.SyntaxKind.DeleteExpression:
case ts.SyntaxKind.AwaitExpression:
case ts.SyntaxKind.PostfixUnaryExpression:
return false;
case ts.SyntaxKind.NewExpression:
return !options.allowNew;
case ts.SyntaxKind.TaggedTemplateExpression:
return !options.allowTaggedTemplate;
case ts.SyntaxKind.BinaryExpression:
return !tsutils_1.isAssignmentKind(node.operatorToken.kind);
case ts.SyntaxKind.PrefixUnaryExpression:
return (node.operator !== ts.SyntaxKind.PlusPlusToken &&
node.operator !== ts.SyntaxKind.MinusMinusToken);
default:
return true;
}
}
function isLiteralZero(node) {
return tsutils_1.isNumericLiteral(node) && node.text === "0";
}
function isIndirectEval(node) {
return (tsutils_1.isIdentifier(node.right) &&
node.right.text === "eval" &&
isLiteralZero(node.left) &&
node.parent.kind === ts.SyntaxKind.ParenthesizedExpression &&
node.parent.parent.kind === ts.SyntaxKind.CallExpression);
}
function isDirective(node) {
if (node.expression.kind !== ts.SyntaxKind.StringLiteral || !canContainDirective(node.parent)) {
return false;
}
var parent = node.parent;
// check if all previous statements in block are also directives
for (var i = parent.statements.indexOf(node) - 1; i >= 0; --i) {
var statement = parent.statements[i];
if (!tsutils_1.isExpressionStatement(statement) ||
statement.expression.kind !== ts.SyntaxKind.StringLiteral) {
return false;
}
}
return true;
}
function canContainDirective(node) {
switch (node.kind) {
case ts.SyntaxKind.SourceFile:
case ts.SyntaxKind.ModuleBlock:
return true;
case ts.SyntaxKind.Block:
switch (node.parent.kind) {
case ts.SyntaxKind.ArrowFunction:
case ts.SyntaxKind.FunctionExpression:
case ts.SyntaxKind.FunctionDeclaration:
case ts.SyntaxKind.MethodDeclaration:
case ts.SyntaxKind.Constructor:
case ts.SyntaxKind.GetAccessor:
case ts.SyntaxKind.SetAccessor:
return true;
default:
return false;
}
default:
return false;
}
}
var templateObject_1, templateObject_2, templateObject_3;