如何从 TypeScript 中的字符串数组创建类型? [英] How do I create a type from a string array in TypeScript?

问题描述

基于字符串数组创建 TypeScript 类型的最佳方法是什么?我使用的是 2.6.2 版.数组很长，我不想通过复制 Enum 声明中的字符串值来重复自己.

What is the best way of making a TypeScript type based on an array of strings? I am on version 2.6.2. The array is long and I do not want to repeat myself by duplicating the string values in an Enum declaration.

我想做的是这样的:

const colors = ['red', 'orange', 'yellow', 'green', 'blue', 'indigo', 'violet'];
export type Color = convertStringArrayToType(colors);

以下解决方案 (source) 工作正常，但感觉很黑:

The following solution (source) works fine, but feels hacky:

/** Utility function to create a K:V from a list of strings */
function strEnum<T extends string>(o: Array<T>): {[K in T]: K} {
  return o.reduce((res, key) => {
    res[key] = key;
    return res;
  }, Object.create(null));
}

/**
  * Sample create a string enum
  */

/** Create a K:V */
const Direction = strEnum([
  'North',
  'South',
  'East',
  'West'
])
/** Create a Type */
type Direction = keyof typeof Direction;

推荐答案

从 Typescript 3.4 开始，您可以使用 as const 并从数组中生成联合类型，如下所示

Since Typescript 3.4, you could use as const and generate a union type from an array as follows

const colors = ['red', 'orange', 'yellow', 'green', 'blue', 'indigo', 'violet'] as const;
export type Color = typeof colors[number]; // 'red'|'orange'|'yellow'|'green'|'blue'|'indigo'|'violet'

这篇关于如何从 TypeScript 中的字符串数组创建类型?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！