no-useless-catch.js

/**
 * @fileoverview Tests for no-useless-throw rule
 * @author Teddy Katz
 * @author Alex Grasley
 */

"use strict";

//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------

const rule = require("../../../lib/rules/no-useless-catch"),
    RuleTester = require("../../../lib/testers/rule-tester");

//------------------------------------------------------------------------------
// Tests
//------------------------------------------------------------------------------

const ruleTester = new RuleTester();

ruleTester.run("no-useless-catch", rule, {
    valid: [
        `
            try {
                foo();
            } catch (err) {
                console.error(err);
            }
        `,
        `
            try {
                foo();
            } catch (err) {
                console.error(err);
            } finally {
                bar();
            }
        `,
        `
            try {
                foo();
            } catch (err) {
                doSomethingBeforeRethrow();
                throw err;
            }
        `,
        `
            try {
                foo();
            } catch (err) {
                throw err.msg;
            }
        `,
        `
            try {
                foo();
            } catch (err) {
                throw new Error("whoops!");
            }
        `,
        `
            try {
                foo();
            } catch (err) {
                throw bar;
            }
        `,
        `
            try {
                foo();
            } catch (err) { }
        `,
        {
            code: `
                try {
                    foo();
                } catch ({ err }) {
                    throw err;
                }
            `,
            parserOptions: { ecmaVersion: 6 }
        },
        {
            code: `
                try {
                    foo();
                } catch ([ err ]) {
                    throw err;
                }
            `,
            parserOptions: { ecmaVersion: 6 }
        },
        {
            code: `
                async () => {
                    try {
                        await doSomething();
                    } catch (e) {
                        doSomethingAfterCatch();
                        throw e;
                    }
                }
            `,
            parserOptions: { ecmaVersion: 8 }
        }

    ],
    invalid: [
        {
            code: `
                try {
                    foo();
                } catch (err) {
                    throw err;
                }
            `,
            errors: [{
                message: "Unnecessary try/catch wrapper.",
                type: "TryStatement"
            }]
        },
        {
            code: `
                try {
                    foo();
                } catch (err) {
                    throw err;
                } finally {
                    foo();
                }
            `,
            errors: [{
                message: "Unnecessary catch clause.",
                type: "CatchClause"
            }]
        },
        {
            code: `
                try {
                    foo();
                } catch (err) {
                    /* some comment */
                    throw err;
                }
            `,
            errors: [{
                message: "Unnecessary try/catch wrapper.",
                type: "TryStatement"
            }]
        },
        {
            code: `
                try {
                    foo();
                } catch (err) {
                    /* some comment */
                    throw err;
                } finally {
                    foo();
                }
            `,
            errors: [{
                message: "Unnecessary catch clause.",
                type: "CatchClause"
            }]
        },
        {
            code: `
                async () => {
                    try {
                        await doSomething();
                    } catch (e) {
                        throw e;
                    }
                }
            `,
            parserOptions: { ecmaVersion: 8 },
            errors: [{
                message: "Unnecessary try/catch wrapper.",
                type: "TryStatement"
            }]
        }
    ]
});