Error when building with ng-packagr/angular

Question

I'm using Angular 7 and building a library with ng-packagr.

After upgrading to latest version of ng-packagr and lodash, I get this error

ERROR: 'isString' is not exported by node_modules\lodash\lodash.js
'isString' is not exported by node_modules\lodash\lodash.js
Error: 'isString' is not exported by node_modules\lodash\lodash.js
    at error (C:\Users\me\myapp\node_modules\rollup\dist\rollup.js:9419:30)
    at Module.error (C:\Users\me\myapp\node_modules\rollup\dist\rollup.js:13402:9)
    at handleMissingExport (C:\Users\me\myapp\node_modules\rollup\dist\rollup.js:13322:21)
    at Module.traceVariable (C:\Users\me\myapp\node_modules\rollup\dist\rollup.js:13711:17)
    at ModuleScope.findVariable (C:\Users\me\myapp\node_modules\rollup\dist\rollup.js:12414:39)
    at FunctionScope.findVariable (C:\Users\me\myapp\node_modules\rollup\dist\rollup.js:2981:38)
    at ChildScope.findVariable (C:\Users\me\myapp\node_modules\rollup\dist\rollup.js:2981:38)
    at FunctionScope.findVariable (C:\Users\me\myapp\node_modules\rollup\dist\rollup.js:2981:38)
    at ChildScope.findVariable (C:\Users\me\myapp\node_modules\rollup\dist\rollup.js:2981:38)
    at Identifier$1.bind (C:\Users\me\myapp\node_modules\rollup\dist\rollup.js:8340:40)
    at CallExpression$1.bind (C:\Users\me\myapp\node_modules\rollup\dist\rollup.js:7969:23)
    at CallExpression$1.bind (C:\Users\me\myapp\node_modules\rollup\dist\rollup.js:10361:15)
    at LogicalExpression.bind (C:\Users\me\myapp\node_modules\rollup\dist\rollup.js:7969:23)
    at LogicalExpression.bind (C:\Users\me\myapp\node_modules\rollup\dist\rollup.js:11150:15)
    at ReturnStatement$1.bind (C:\Users\me\myapp\node_modules\rollup\dist\rollup.js:7969:23)
    at BlockStatement$1.bind (C:\Users\me\myapp\node_modules\rollup\dist\rollup.js:7965:31)

Any idea how to fix it?

Answer 1

What worked for me was to replace

import { isString } from "lodash";

with

import { isString } from "lodash-es";