Property 'trimLeft' does not exist on type 'string'. Lib: ["dom", "es2018"]

Question

I am getting this Error when running the following code

let foo = '  foo  '
console.log(foo.trimLeft())
//foo.trimStart() works neither

I know most of the solutions in the internet say, that I have to fix my tsconfig.json to include es20whatever.

The funny thing is, I can use es2018 stuff like Promise.prototype.finally and rest spread etc. VSCode also auto completes trimStart() for me which is odd, because the project and the editor should use the same tsconfig.json. But this particular piece of code does not compile.

Here is my tsconfig.json

{
  "compileOnSave": false,
  "compilerOptions": {
    "outDir": "./dist/out-tsc",
    "baseUrl": "./",
    "sourceMap": true,
    "declaration": false,
    "moduleResolution": "node",
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "target": "es5",
    "typeRoots": ["node_modules/@types"],
    "lib": ["es2018", "dom"],
    "plugins": [
      {
        "name": "tslint-language-service",
        "configFile": "./tslint.json"
      }
    ],
    "paths": {
      "foo": ["projects/foo/src/public_api.ts"],
      "bar": ["projects/bar/src/public_api.ts"],
      "baz": ["dist/baz"]
    }
  }
}

I am running this in a monorepo angular folder (as you can see above). Perhaps there is an issue with that, I don't know.

Compile time error. I can run it perfectly on the browser console — uloco, Jan 30 '19 at 13:06
Interesting, because when I got the "Property 'trimRight' does not exist on type 'string'." error adding es2018 to the lib array was enough to solve my problem. — webpreneur, Dec 04 '20 at 14:01

score 14 · Accepted Answer · answered Jun 03 '19 at 21:41

14

Include the library "es2019.string". Update your copy of Typescript if there is no such library. It is rather new and did not exist when this question was asked.

answered Jun 03 '19 at 21:41

Mushinako

312
3
9

score 11 · Answer 2 · answered Aug 29 '19 at 09:17

11

Update the typescript library to "typescript": "~3.6.2". Include "es2019" in the tsconfig.json lib's array. It will work.

"target": "es2015",
"typeRoots": [
  "node_modules/@types"
],
"lib": [
  "es2018",
  "es2019",
  "dom"
]

answered Aug 29 '19 at 09:17

mshahin364

169
2
3

Interesting, because for me, adding es2018 to the lib array did the job. – webpreneur Dec 04 '20 at 13:59

score 0 · Answer 3 · answered Jan 30 '19 at 10:32

I don't think es2018 is going to work. Try changing it to "es2016"

{
  "compileOnSave": false,
  "compilerOptions": {
    "outDir": "./dist/out-tsc",
    "baseUrl": "./",
    "sourceMap": true,
    "declaration": false,
    "moduleResolution": "node",
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "target": "es5",
    "typeRoots": ["node_modules/@types"],
    "lib": ["es2016", "dom"],
    "plugins": [
      {
        "name": "tslint-language-service",
        "configFile": "./tslint.json"
      }
    ],
    "paths": {
      "foo": ["projects/foo/src/public_api.ts"],
      "bar": ["projects/bar/src/public_api.ts"],
      "baz": ["dist/baz"]
    }
  }
}

Property 'trimLeft' does not exist on type 'string'. Lib: ["dom", "es2018"]

3 Answers3