基于Typescript和Jest刷题环境搭建与使用

写在前面

前几个月在公司用vue3和ts写项目，想巩固一下基础，于是我想起了去年基于JavaScript和Jest搭建的刷题环境，不如，给它搞个加强版，结合Typescript和Jest 搞一个刷题环境，下面是我的一些使用心得，分享给大家。

介绍

Typescript是JavaScript的超集，是前端工程师需要掌握的一门语言。Jest是一个测试框架，具体的可以看我早年写的文章https://www.cnblogs.com/cnroadbridge/p/13524099.html， Babel是一个语言编译器，具体的也可以看我早年写的文章https://www.cnblogs.com/cnroadbridge/p/13311360.html。

环境搭建

前期工作

这里统一用yarn 来进行相关的npm 包安装与维护，使用其他安装管理工具的参照着这个改吧。

创建项目并初始化

mkdir coding-ts && cd coding-ts
npm init -y

安装ts的开发环境依赖

yarn add typescript ts-node @types/node -D

配置tsconfig.json

{
"compilerOptions": {
/* Visit https://aka.ms/tsconfig.json to read more about this file */

/* Projects */
// "incremental": true,                              /* Enable incremental compilation */
// "composite": true,                                /* Enable constraints that allow a TypeScript project to be used with project references. */
// "tsBuildInfoFile": "./",                          /* Specify the folder for .tsbuildinfo incremental compilation files. */
// "disableSourceOfProjectReferenceRedirect": true,  /* Disable preferring source files instead of declaration files when referencing composite projects */
// "disableSolutionSearching": true,                 /* Opt a project out of multi-project reference checking when editing. */
// "disableReferencedProjectLoad": true,             /* Reduce the number of projects loaded automatically by TypeScript. */

/* Language and Environment */
"target": "es2016",                                  /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
// "lib": [],                                        /* Specify a set of bundled library declaration files that describe the target runtime environment. */
// "jsx": "preserve",                                /* Specify what JSX code is generated. */
// "experimentalDecorators": true,                   /* Enable experimental support for TC39 stage 2 draft decorators. */
// "emitDecoratorMetadata": true,                    /* Emit design-type metadata for decorated declarations in source files. */
// "jsxFactory": "",                                 /* Specify the JSX factory function used when targeting React JSX emit, e.g. 'React.createElement' or 'h' */
// "jsxFragmentFactory": "",                         /* Specify the JSX Fragment reference used for fragments when targeting React JSX emit e.g. 'React.Fragment' or 'Fragment'. */
// "jsxImportSource": "",                            /* Specify module specifier used to import the JSX factory functions when using `jsx: react-jsx*`.` */
// "reactNamespace": "",                             /* Specify the object invoked for `createElement`. This only applies when targeting `react` JSX emit. */
// "noLib": true,                                    /* Disable including any library files, including the default lib.d.ts. */
// "useDefineForClassFields": true,                  /* Emit ECMAScript-standard-compliant class fields. */

/* Modules */
"module": "commonjs",                                /* Specify what module code is generated. */
// "rootDir": "./",                                  /* Specify the root folder within your source files. */
// "moduleResolution": "node",                       /* Specify how TypeScript looks up a file from a given module specifier. */
// "baseUrl": "./",                                  /* Specify the base directory to resolve non-relative module names. */
// "paths": {},                                      /* Specify a set of entries that re-map imports to additional lookup locations. */
// "rootDirs": [],                                   /* Allow multiple folders to be treated as one when resolving modules. */
// "typeRoots": [],                                  /* Specify multiple folders that act like `./node_modules/@types`. */
// "types": [],                                      /* Specify type package names to be included without being referenced in a source file. */
// "allowUmdGlobalAccess": true,                     /* Allow accessing UMD globals from modules. */
// "resolveJsonModule": true,                        /* Enable importing .json files */
// "noResolve": true,                                /* Disallow `import`s, `require`s or `<reference>`s from expanding the number of files TypeScript should add to a project. */

/* JavaScript Support */
// "allowJs": true,                                  /* Allow JavaScript files to be a part of your program. Use the `checkJS` option to get errors from these files. */
// "checkJs": true,                                  /* Enable error reporting in type-checked JavaScript files. */
// "maxNodeModuleJsDepth": 1,                        /* Specify the maximum folder depth used for checking JavaScript files from `node_modules`. Only applicable with `allowJs`. */

/* Emit */
// "declaration": true,                              /* Generate .d.ts files from TypeScript and JavaScript files in your project. */
// "declarationMap": true,                           /* Create sourcemaps for d.ts files. */
// "emitDeclarationOnly": true,                      /* Only output d.ts files and not JavaScript files. */
"sourceMap": true,                                /* Create source map files for emitted JavaScript files. */
// "outFile": "./",                                  /* Specify a file that bundles all outputs into one JavaScript file. If `declaration` is true, also designates a file that bundles all .d.ts output. */
"outDir": "dist",                                   /* Specify an output folder for all emitted files. */
// "removeComments": true,                           /* Disable emitting comments. */
// "noEmit": true,                                   /* Disable emitting files from a compilation. */
// "importHelpers": true,                            /* Allow importing helper functions from tslib once per project, instead of including them per-file. */
// "importsNotUsedAsValues": "remove",               /* Specify emit/checking behavior for imports that are only used for types */
// "downlevelIteration": true,                       /* Emit more compliant, but verbose and less performant JavaScript for iteration. */
// "sourceRoot": "",                                 /* Specify the root path for debuggers to find the reference source code. */
// "mapRoot": "",                                    /* Specify the location where debugger should locate map files instead of generated locations. */
// "inlineSourceMap": true,                          /* Include sourcemap files inside the emitted JavaScript. */
// "inlineSources": true,                            /* Include source code in the sourcemaps inside the emitted JavaScript. */
// "emitBOM": true,                                  /* Emit a UTF-8 Byte Order Mark (BOM) in the beginning of output files. */
// "newLine": "crlf",                                /* Set the newline character for emitting files. */
// "stripInternal": true,                            /* Disable emitting declarations that have `@internal` in their JSDoc comments. */
// "noEmitHelpers": true,                            /* Disable generating custom helper functions like `__extends` in compiled output. */
// "noEmitOnError": true,                            /* Disable emitting files if any type checking errors are reported. */
// "preserveConstEnums": true,                       /* Disable erasing `const enum` declarations in generated code. */
// "declarationDir": "./",                           /* Specify the output directory for generated declaration files. */
// "preserveValueImports": true,                     /* Preserve unused imported values in the JavaScript output that would otherwise be removed. */

/* Interop Constraints */
// "isolatedModules": true,                          /* Ensure that each file can be safely transpiled without relying on other imports. */
// "allowSyntheticDefaultImports": true,             /* Allow 'import x from y' when a module doesn't have a default export. */
"esModuleInterop": true,                             /* Emit additional JavaScript to ease support for importing CommonJS modules. This enables `allowSyntheticDefaultImports` for type compatibility. */
// "preserveSymlinks": true,                         /* Disable resolving symlinks to their realpath. This correlates to the same flag in node. */
"forceConsistentCasingInFileNames": true,            /* Ensure that casing is correct in imports. */

/* Type Checking */
"strict": true,                                      /* Enable all strict type-checking options. */
// "noImplicitAny": true,                            /* Enable error reporting for expressions and declarations with an implied `any` type.. */
// "strictNullChecks": true,                         /* When type checking, take into account `null` and `undefined`. */
// "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
// "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
// "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
// "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
// "useUnknownInCatchVariables": true,               /* Type catch clause variables as 'unknown' instead of 'any'. */
// "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
// "noUnusedLocals": true,                           /* Enable error reporting when a local variables aren't read. */
// "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
// "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
// "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
// "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
// "noUncheckedIndexedAccess": true,                 /* Include 'undefined' in index signature results */
// "noImplicitOverride": true,                       /* Ensure overriding members in derived classes are marked with an override modifier. */
// "noPropertyAccessFromIndexSignature": true,       /* Enforces using indexed accessors for keys declared using an indexed type */
// "allowUnusedLabels": true,                        /* Disable error reporting for unused labels. */
// "allowUnreachableCode": true,                     /* Disable error reporting for unreachable code. */

/* Completeness */
// "skipDefaultLibCheck": true,                      /* Skip type checking .d.ts files that are included with TypeScript. */
"skipLibCheck": true                                 /* Skip type checking all .d.ts files. */
}
}

这里也可以用

tsc --init

安装jest的开发环境依赖

yarn add jest ts-jest @types/jest -D

配置jest.config.js

/** @type {import('ts-jest/dist/types').InitialOptionsTsJest} */

/*
* For a detailed explanation regarding each configuration property, visit:
* https://jestjs.io/docs/en/configuration.html
*/

module.exports = {
// All imported modules in your tests should be mocked automatically
// automock: false,

// Stop running tests after `n` failures
// bail: 0,

// The directory where Jest should store its cached dependency information
// cacheDirectory: "/private/var/folders/6j/_9wqvbk15bl701f7ch11q9p80000gn/T/jest_dx",

// Automatically clear mock calls and instances between every test
clearMocks: true,

// Indicates whether the coverage information should be collected while executing the test
// collectCoverage: false,

// An array of glob patterns indicating a set of files for which coverage information should be collected
// collectCoverageFrom: undefined,

// The directory where Jest should output its coverage files
coverageDirectory: 'coverage',

// An array of regexp pattern strings used to skip coverage collection
// coveragePathIgnorePatterns: [
//   "/node_modules/"
// ],

// Indicates which provider should be used to instrument code for coverage
// coverageProvider: "babel",

// A list of reporter names that Jest uses when writing coverage reports
// coverageReporters: [
//   "json",
//   "text",
//   "lcov",
//   "clover"
// ],

// An object that configures minimum threshold enforcement for coverage results
// coverageThreshold: undefined,

// A path to a custom dependency extractor
// dependencyExtractor: undefined,

// Make calling deprecated APIs throw helpful error messages
// errorOnDeprecated: false,

// Force coverage collection from ignored files using an array of glob patterns
// forceCoverageMatch: [],

// A path to a module which exports an async function that is triggered once before all test suites
// globalSetup: undefined,

// A path to a module which exports an async function that is triggered once after all test suites
// globalTeardown: undefined,

// A set of global variables that need to be available in all test environments
// globals: {},

// The maximum amount of workers used to run your tests. Can be specified as % or a number. E.g. maxWorkers: 10% will use 10% of your CPU amount + 1 as the maximum worker number. maxWorkers: 2 will use a maximum of 2 workers.
// maxWorkers: "50%",

// An array of directory names to be searched recursively up from the requiring module's location
// moduleDirectories: [
//   "node_modules"
// ],

// An array of file extensions your modules use
// moduleFileExtensions: [
//   "js",
//   "json",
//   "jsx",
//   "ts",
//   "tsx",
//   "node"
// ],

// A map from regular expressions to module names or to arrays of module names that allow to stub out resources with a single module
// moduleNameMapper: {},

// An array of regexp pattern strings, matched against all module paths before considered 'visible' to the module loader
// modulePathIgnorePatterns: [],

// Activates notifications for test results
// notify: false,

// An enum that specifies notification mode. Requires { notify: true }
// notifyMode: "failure-change",

// A preset that is used as a base for Jest's configuration
preset: 'ts-jest',

// Run tests from one or more projects
// projects: undefined,

// Use this configuration option to add custom reporters to Jest
// reporters: undefined,

// Automatically reset mock state between every test
// resetMocks: false,

// Reset the module registry before running each individual test
// resetModules: false,

// A path to a custom resolver
// resolver: undefined,

// Automatically restore mock state between every test
// restoreMocks: false,

// The root directory that Jest should scan for tests and modules within
// rootDir: undefined,

// A list of paths to directories that Jest should use to search for files in
// roots: [
//   "<rootDir>"
// ],

// Allows you to use a custom runner instead of Jest's default test runner
// runner: "jest-runner",

// The paths to modules that run some code to configure or set up the testing environment before each test
// setupFiles: [],

// A list of paths to modules that run some code to configure or set up the testing framework before each test
// setupFilesAfterEnv: [],

// The number of seconds after which a test is considered as slow and reported as such in the results.
// slowTestThreshold: 5,

// A list of paths to snapshot serializer modules Jest should use for snapshot testing
// snapshotSerializers: [],

// The test environment that will be used for testing
testEnvironment: 'node',

// Options that will be passed to the testEnvironment
// testEnvironmentOptions: {},

// Adds a location field to test results
// testLocationInResults: false,

// The glob patterns Jest uses to detect test files
// testMatch: [
//   "**/__tests__/**/*.[jt]s?(x)",
//   "**/?(*.)+(spec|test).[tj]s?(x)"
// ],

// An array of regexp pattern strings that are matched against all test paths, matched tests are skipped
// testPathIgnorePatterns: [
//   "/node_modules/"
// ],

// The regexp pattern or array of patterns that Jest uses to detect test files
// testRegex: [],

// This option allows the use of a custom results processor
// testResultsProcessor: undefined,

// This option allows use of a custom test runner
// testRunner: "jasmine2",

// This option sets the URL for the jsdom environment. It is reflected in properties such as location.href
// testURL: "http://localhost",

// Setting this value to "fake" allows the use of fake timers for functions such as "setTimeout"
// timers: "real",

// A map from regular expressions to paths to transformers
// transform: undefined,

// An array of regexp pattern strings that are matched against all source file paths, matched files will skip transformation
// transformIgnorePatterns: [
//   "/node_modules/",
//   "\\.pnp\\.[^\\/]+$"
// ],

// An array of regexp pattern strings that are matched against all modules before the module loader will automatically return a mock for them
// unmockedModulePathPatterns: undefined,

// Indicates whether each individual test should be reported during the run
// verbose: undefined,

// An array of regexp patterns that are matched against all source file paths before re-running tests in watch mode
// watchPathIgnorePatterns: [],

// Whether to use watchman for file crawling
// watchman: true,
};

安装babel的开发环境依赖

yarn add babel-jest @babel/core @babel/preset-env @babel/preset-typescript -D

配置babel.config.js

module.exports = {
presets: [
['@babel/preset-env', { targets: { node: 'current' } }],
'@babel/preset-typescript',
],
};

具体的参考这里，https://jestjs.io/docs/getting-started

安装prettier 和 eslint的开发环境依赖

yarn add prettier onchange eslint-config-prettier eslint-plugin-prettier -D

配置.prettierrc和.prettierignore

.prettierrc

{
"semi": true,
"tabWidth": 2,
"printWidth": 120,
"endOfLine": "lf",
"singleQuote": true,
"trailingComma": "es5",
"bracketSpacing": true,
"alwaysParens": "always",
"eslintIntegration": true,
"jsxSingleQuote": true
}

.prettierignore

# Ignore artifacts:
coverage
# ignore dependency folder
node_modules/

配置.eslintrc

{
"root": true,
"parser": "@typescript-eslint/parser",
"plugins": [
"@typescript-eslint",
"prettier"
],
"extends": [
"eslint:recommended",
"plugin:@typescript-eslint/eslint-recommended",
"plugin:@typescript-eslint/recommended",
"prettier"
],
"rules": {
"no-console": 1,       // Means warning
"prettier/prettier": 2 // Means error
}
}

具体的可以参考这里，https://khalilstemmler.com/blogs/tooling/prettier/

配置package.json的相关script

"scripts": {
"build": "tsc",
"test": "jest",
"test:help": "jest --help",
"test:debug": "jest --debug",
"test:verbose": "jest --verbose",
"test:init": "jest --init",
"test:json": "jest --json",
"test:exportJson": "jest --json --outputFile=./export/reporter.json",
"test:coverage": "jest --coverage",
"test:watchAll": "jest --watchAll",
"pretty": "prettier --config .prettierrc \"code/**/*.ts\" --write",
"pretty-watch": "onchange \"code/**/*.ts\" -- prettier --write {{changed}}",
"git:pull": "pull",
"git:push": "push"
}

测试案例

这里以两数之和为例，做一个简单的代码测试，具体的如下：

源码

// code/sum.ts 两数之和测试案例
type sumType = (a: number, b: number) => number;
const sum: sumType = (a, b) => a + b;
export default sum;

测试代码

// test/sum.test.ts
import sum from '../code/sum';

test('1 + 2 = 3', () => {
let x: number = 1, y: number = 2;
let expected: number = 3;

let res: number = sum(x, y);

expect(res).toBe(expected);
});

在项目文件下执行

yarn test

PS D:\ataola\github\ataola\coding-ts> yarn test
yarn run v1.22.11
$ jest
PASS  test/sum.test.ts (8.801 s)
√ 1 + 2 = 3 (2 ms)

Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        10.721 s
Ran all test suites.
Done in 26.79s.
PS D:\ataola\github\ataola\coding-ts>

持续集成和代码覆盖率

Travis可以对项目做一个持续集成 ，结合Codecov，可以对代码覆盖率做一个测试，这样项目看上去就丰满了很多

关于Travis和Codecov的相关实践，具体的可以参见https://www.cnblogs.com/cnroadbridge/p/14716361.html

写在后面

项目地址： https://github.com/ataola/coding-ts

线上访问地址: https://zhengjiangtao.cn/coding-ts/

感谢阅读！