如何將 web3.js@1.0.0-beta34 與 TypeScript 一起使用？

這是用於測試的最小程式碼：

import * as Web3 from "web3"

const web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:7545"))

const main = async () => {
 const blockNumber = await web3.eth.getBlockNumber()
 console.log({ blockNumber })
}

main().catch(err => console.error(err))

模組類型錯誤。如果我嘗試編譯它，會出現一些錯誤：

maxblock@mbp t10-web3-typescript *$ npm run build

> t10-web3-typescript@1.0.0 build /Users/maxblock/projects/test/t10-web3-typescript
> rimraf dist && tsc

../../../node_modules/web3/types.d.ts(1,27): error TS7016: Could not find a declaration file for module 'bn.js'. '/Users/maxblock/node_modules/bn.js/lib/bn.js' implicitly has an 'any' type.
 Try `npm install @types/bn.js` if it exists or add a new declaration (.d.ts) file containing `declare module 'bn.js';`
../../../node_modules/web3/types.d.ts(2,21): error TS7016: Could not find a declaration file for module 'underscore'. '/Users/maxblock/node_modules/underscore/underscore.js' implicitly has an 'any' type.
 Try `npm install @types/underscore` if it exists or add a new declaration (.d.ts) file containing `declare module 'underscore';`
src/index.ts(3,14): error TS2351: Cannot use 'new' with an expression whose type lacks a call or construct signature.
src/index.ts(3,32): error TS2339: Property 'providers' does not exist on type 'typeof "/Users/maxblock/node_modules/web3/index"'.

好的。接下來，我嘗試用自己的類型覆蓋類型。出於這個原因，我創建了一個帶有簡單存根的文件 typings.d.ts: declare module "web3"。

我自己的打字錯誤較少，但無論如何我無法編譯它：

maxblock@mbp t10-web3-typescript *$ npm run build

> t10-web3-typescript@1.0.0 build /Users/maxblock/projects/test/t10-web3-typescript
> rimraf dist && rimraf node_modules/web3/index.d.ts && rimraf node_modules/web3/types.d.ts && tsc

../../../node_modules/web3/types.d.ts(1,27): error TS7016: Could not find a declaration file for module 'bn.js'. '/Users/maxblock/node_modules/bn.js/lib/bn.js' implicitly has an 'any' type.
 Try `npm install @types/bn.js` if it exists or add a new declaration (.d.ts) file containing `declare module 'bn.js';`
../../../node_modules/web3/types.d.ts(2,21): error TS7016: Could not find a declaration file for module 'underscore'. '/Users/maxblock/node_modules/underscore/underscore.js' implicitly has an 'any' type.
 Try `npm install @types/underscore` if it exists or add a new declaration (.d.ts) file containing `declare module 'underscore';`

我什至嘗試刪除 node_modules/web3/index.d.ts 和 node_modules/web3/types.d.ts 文件，但沒有成功。

你如何使用 web3.js + TypeScript？

在您所在的項目根文件夾下package.json，執行以下命令：

npm install --save-dev @types/underscore
npm install bignumber.js

或者

yarn add @types/underscore --dev
yarn add bignumber.js

編輯第一行<rootDir>/node_moduoles/web3/types.d.ts如下：

-- import { BigNumber } from 'bn.js'
++ import { BigNumber } from 'bignumber.js'

你的程式碼應該編譯

對我有用的是：

1. 安裝node類型。

npm install @types/node --save 

2. 在 中指定node類型tsconfig.json：

{
 "compilerOptions": {
   // rest ommitted,
   "types": ["node"]
 },
 "typeRoots": [
   "./node_modules/@types"
 ]
}

3. 使用require語法而不是import * as Web3 from 'web3';：

const Web3 = require('web3');

引用自：https://ethereum.stackexchange.com/questions/47055