[英]Typescript allows to save wrong types. why?
I'm using Typescript in NodeJS.我在 NodeJS 中使用 Typescript。 I defined an
interface
and I passed it to the variable.我定义了一个
interface
并将其传递给变量。 But when I send some data that is not match with interface
type for example I pass number
instead of string
for text property
that I created in interface
, Typescirpt still can save them in the variable.但是当我发送一些与
interface
类型不匹配的数据时,例如我为我在interface
中创建的text property
传递number
而不是string
,Typescirpt 仍然可以将它们保存在变量中。 In react.js
I had the same issue.在
react.js
我有同样的问题。
Code is very simple, and I'm using the memory of nodejs to make that typescript works fine:代码非常简单,我使用 nodejs 的 memory 使 typescript 工作正常:
models-types file:模型类型文件:
export interface Todo {
id: string;
text: string;
}
Controller file: Controller 文件:
import { RequestHandler } from "express";
import { Todo } from "../models/todo";
const data: Todo[] = [];
export const todoPostHandler: RequestHandler = (req, res, next) => {
try {
const text = (req.body as { text: string }).text;
if (!text) {
throw { message: "invalid text" };
}
const incomingData = { id: Math.random().toString(), text };
data.push(incomingData);
res.status(201).json({ message: "data created in the server", data: incomingData });
} catch (error) {
return next(error);
}
};
Json file: Json 文件:
{
"compilerOptions": {
/* Visit https://aka.ms/tsconfig.json to read more about this file */
/* Basic Options */
// "incremental": true, /* Enable incremental compilation */
"target": "es2018" /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019', 'ES2020', or 'ESNEXT'. */,
"module": "commonjs",
"moduleResolution": "node" /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', 'es2020', or 'ESNext'. */,
// "lib": [], /* Specify library files to be included in the compilation. */
// "allowJs": true, /* Allow javascript files to be compiled. */
// "checkJs": true, /* Report errors in .js files. */
// "jsx": "preserve", /* Specify JSX code generation: 'preserve', 'react-native', or 'react'. */
// "declaration": true, /* Generates corresponding '.d.ts' file. */
// "declarationMap": true, /* Generates a sourcemap for each corresponding '.d.ts' file. */
// "sourceMap": true, /* Generates corresponding '.map' file. */
// "outFile": "./", /* Concatenate and emit output to single file. */
"outDir": "./dist" /* Redirect output structure to the directory. */,
"rootDir": "./src" /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */,
// "composite": true, /* Enable project compilation */
// "tsBuildInfoFile": "./", /* Specify file to store incremental compilation information */
// "removeComments": true, /* Do not emit comments to output. */
// "noEmit": true, /* Do not emit outputs. */
// "importHelpers": true, /* Import emit helpers from 'tslib'. */
// "downlevelIteration": true, /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */
// "isolatedModules": true, /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */
/* Strict Type-Checking Options */
"strict": true /* Enable all strict type-checking options. */,
// "noImplicitAny": true, /* Raise error on expressions and declarations with an implied 'any' type. */
// "strictNullChecks": true, /* Enable strict null checks. */
// "strictFunctionTypes": true, /* Enable strict checking of function types. */
// "strictBindCallApply": true, /* Enable strict 'bind', 'call', and 'apply' methods on functions. */
// "strictPropertyInitialization": true, /* Enable strict checking of property initialization in classes. */
// "noImplicitThis": true, /* Raise error on 'this' expressions with an implied 'any' type. */
// "alwaysStrict": true, /* Parse in strict mode and emit "use strict" for each source file. */
/* Additional Checks */
// "noUnusedLocals": true, /* Report errors on unused locals. */
// "noUnusedParameters": true, /* Report errors on unused parameters. */
// "noImplicitReturns": true, /* Report error when not all code paths in function return a value. */
// "noFallthroughCasesInSwitch": true, /* Report errors for fallthrough cases in switch statement. */
// "noUncheckedIndexedAccess": true, /* Include 'undefined' in index signature results */
/* Module Resolution Options */
// "moduleResolution": "node", /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
// "baseUrl": "./", /* Base directory to resolve non-absolute module names. */
// "paths": {}, /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
// "rootDirs": [], /* List of root folders whose combined content represents the structure of the project at runtime. */
// "typeRoots": [], /* List of folders to include type definitions from. */
// "types": [], /* Type declaration files to be included in compilation. */
// "allowSyntheticDefaultImports": true, /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */
"esModuleInterop": true /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */,
// "preserveSymlinks": true, /* Do not resolve the real path of symlinks. */
// "allowUmdGlobalAccess": true, /* Allow accessing UMD globals from modules. */
/* Source Map Options */
// "sourceRoot": "", /* Specify the location where debugger should locate TypeScript files instead of source locations. */
// "mapRoot": "", /* Specify the location where debugger should locate map files instead of generated locations. */
// "inlineSourceMap": true, /* Emit a single file with source maps instead of having a separate file. */
// "inlineSources": true, /* Emit the source alongside the sourcemaps within a single file; requires '--inlineSourceMap' or '--sourceMap' to be set. */
/* Experimental Options */
// "experimentalDecorators": true, /* Enables experimental support for ES7 decorators. */
// "emitDecoratorMetadata": true, /* Enables experimental support for emitting type metadata for decorators. */
/* Advanced Options */
"skipLibCheck": true /* Skip type checking of declaration files. */,
"forceConsistentCasingInFileNames": true /* Disallow inconsistently-cased references to the same file. */
}
}
TypeScript doesn't check any types at runtime. TypeScript 在运行时不检查任何类型。
If you use X as Y
you basically pinky-swear that the data X
is of the type Y
and TypeScript will believe you.如果您将
X as Y
,您基本上会发誓数据X
属于Y
类型,并且 TypeScript 会相信您。
If you don't want to do that, you'll need a "codec" at the "edge" of the TypeScript world that will choke on data that is actually invalid;如果您不想这样做,您将需要在 TypeScript 世界的“边缘”有一个“编解码器”,它会阻塞实际上无效的数据; Zod is a fairly popular TypeScript-native choice to deserialize and schema-validate data.
Zod是一种相当流行的 TypeScript 原生选择,用于反序列化和模式验证数据。 Other choices include eg io-ts .
其他选择包括例如io-ts 。
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