Using BigInt in TypeScript

Question

I believe I should be able to use BigInt now in TypeScript...but changing some code base to use it and I get "Cannot find name 'BigInt'. (2304)" any thought on why I am getting this error?

$ cat test.ts 
let x = BigInt(123)
console.log(x.toString())

$ tsc test.ts 
test.ts:1:9 - error TS2304: Cannot find name 'BigInt'.

1 let x = BigInt(123)
          ~~~~~~


Found 1 error.

How do I start using BigInt now within TypeScript?

Answer 1

BigInt support has been added on TypeScript 3.2; make sure your version is compatible.

But on top of that, you need to decide how BigInt will be supported on the context of your script - will you provide polyfills, or will you only run your script on environments that are guaranteed to have BigInt support?

This means you will need esnext as your build target (likely on tsconfig.json's target field), since BigInt is not compatible with previous ECMAScript versions.

If you do include a BigInt polyfill, you can use esnext.bigint as part of the lib field during transpilation. This adds the needed definitions to the process.

Answer 2

It works for me to add esnext.bigint in lib .

{
  "compilerOptions": {
    "lib": ["es6","esnext.bigint"]
  }
}

Answer 3

In my case, I should be add "node" to types in my tsconfig.json

{
  "compilerOptions": {
    "target": "esnext",
    "outDir": "build/module",
    "module": "esnext",
    "types": ["node"]
  },
  "exclude": [
    "node_modules/**"
  ]
}