CODEWITHSUNDEEP
angulartypescriptlodash
Serge Intern
Serge Intern

Reputation: 2969

Cannot just import lodash.add in my angular 4 project

I'm trying to just import the add method of lodash using angular4+typescript.

I tried a lot of differents things:

import { add } from 'lodash';
import { add } from 'lodash/add';
import * as add from 'lodash/add';
import { add } from 'lodash.add';
import * as add from 'lodash.add';

(and others I've forgotten)

Here's my latest (desesperate?) attempt at achieving this:

import { Component, OnInit } from '@angular/core';
import add = require('lodash.add');

@Component({
  selector: 'app-test',
  templateUrl: './test.component.html',
  styleUrls: ['./test.component.css']
})
export class TestComponent implements OnInit {
  private x: number;

  constructor() { }

  ngOnInit() {
    let y = add(5, 5);
  }

}

But it doesn't work.

When I "ng serve" I get the message:

ERROR in ...test.component.ts (2,1): Import assignment cannot be used when targeting ECMAScript 2015 modules. Consider using 'import * as ns from "mod"', 'import {a} from "mod"', 'import d from "mod"', or another module format instead.)

My package config:

{
  "name": "treeshake",
  "version": "0.0.0",
  "license": "MIT",
  "angular-cli": {},
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/common": "^2.4.0",
    "@angular/compiler": "^2.4.0",
    "@angular/core": "^2.4.0",
    "@angular/forms": "^2.4.0",
    "@angular/http": "^2.4.0",
    "@angular/platform-browser": "^2.4.0",
    "@angular/platform-browser-dynamic": "^2.4.0",
    "@angular/router": "^3.4.0",
    "@types/lodash": "lattest",
    "@types/lodash.add": "^3.7.2",
    "core-js": "^2.4.1",
    "lodash": "^4.17.4",
    "lodash.add": "^3.7.0",
    "rxjs": "^5.4.2",
    "zone.js": "^0.7.6"
  },
  "devDependencies": {
    "@angular/cli": "1.0.0-beta.32.3",
    "@angular/compiler-cli": "^2.4.0",
    "@types/jasmine": "2.5.38",
    "@types/node": "~6.0.60",
    "codelyzer": "~2.0.0-beta.4",
    "jasmine-core": "~2.5.2",
    "jasmine-spec-reporter": "~3.2.0",
    "karma": "~1.4.1",
    "karma-chrome-launcher": "~2.0.0",
    "karma-cli": "~1.0.1",
    "karma-coverage-istanbul-reporter": "^0.2.0",
    "karma-jasmine": "~1.1.0",
    "karma-jasmine-html-reporter": "^0.2.2",
    "protractor": "~5.1.0",
    "ts-node": "~2.0.0",
    "tslint": "~4.4.2",
    "typescript": "^2.4.1"
  }
}

and my tsconfig.json

{
  "compilerOptions": {
    "baseUrl": "",
    "declaration": false,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "lib": [
      "es2016",
      "dom"
    ],
    "mapRoot": "./",
    "module": "es2015",
    "moduleResolution": "node",
    "outDir": "../dist/out-tsc",
    "sourceMap": true,
    "target": "es5",
    "typeRoots": [
      "../node_modules/@types"
    ]
  }
}

Upvotes: 2

Views: 1403

Answers (2)

Eric Simonton
Eric Simonton

Reputation: 6029

I recommend using lodash-es, which is a the same lodash but distributed with each function as a separate ECMA Script module. Then to import just the code needed for the add function you:

import add from 'lodash-es/add'

Note that it also has its own @types/lodash-es package to use instead of @types/lodash.

Upvotes: 3

Aravind
Aravind

Reputation: 41533

Your version in package.json is wrong. Correct the typo

@types/lodash": "lattest",

You should be importing the lodash as 

import * as _ from 'lodash';

Ensure that you have lodash listed in the typings.json file

Update 1:

Install typings globally using 

npm install typings -g

Then install lodash through typings as

typings install lodash --save

Use the import statement as 

import { add } from 'lodash';

Upvotes: 1

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