Uncaught Error: Expected 'styles' to be an array of strings. about ngx-quill-editor

[rajsibi7]

I am working on two projects, one is angular 2 and another one is angular 4, in angular 2 projects it works fine but in angular 4 it throws the below error.
Uncaught Error: Expected 'styles' to be an array of strings. at assertArrayOfStrings (compiler.es5.js:3351) [<root>] at CompileMetadataResolver.webpackJsonp.../../../compiler/@angular/compiler.es5.js.CompileMetadataResolver.getNonNormalizedDirectiveMetadata (compiler.es5.js:13775) [<root>] at CompileMetadataResolver.webpackJsonp.../../../compiler/@angular/compiler.es5.js.CompileMetadataResolver._loadDirectiveMetadata (compiler.es5.js:13693) [<root>] at vendor.bundle.js:92249:54 [<root>] at Array.forEach (<anonymous>) [<root>] at CompileMetadataResolver.webpackJsonp.../../../compiler/@angular/compiler.es5.js.CompileMetadataResolver.loadNgModuleDirectiveAndPipeMetadata (compiler.es5.js:13916) [<root>] at vendor.bundle.js:103416:58 [<root>] at Array.forEach (<anonymous>) [<root>] at JitCompiler.webpackJsonp.../../../compiler/@angular/compiler.es5.js.JitCompiler._loadModules (compiler.es5.js:25083) [<root>] at JitCompiler.webpackJsonp.../../../compiler/@angular/compiler.es5.js.JitCompiler._compileModuleAndComponents (compiler.es5.js:25037) [<root>] at JitCompiler.webpackJsonp.../../../compiler/@angular/compiler.es5.js.JitCompiler.compileModuleAsync (compiler.es5.js:24999) [<root>] at PlatformRef_.webpackJsonp.../../../core/@angular/core.es5.js.PlatformRef_._bootstrapModuleWithZone (core.es5.js:4786) [<root>] at PlatformRef_.webpackJsonp.../../../core/@angular/core.es5.js.PlatformRef_.bootstrapModule (core.es5.js:4772) [<root>] at Object.../../../../../src/main.ts (main.ts:11) [<root>]