Angular Argument of type 'array' is not assignable to parameter of type 'string'

Question

I have json:

  public example=[{
       array:[item1, item2,]
    },
    {
       array:[item1, item2,]
    }]

file html:

<div *ngFor="let item of example">
      <div *ngIf="check(item.array)"> ...</div>
</div>

but call function check inside ngOnInit(), it error

 check(...request: string[]){
        return this._RolesService.checkRoles(request);
    }

ngOnInit(): void {
       let req:string[] = ['string1'];
        if(this.check(req)){}
}

gender html is ok, so When i call function check() in ngOnInit, it had error: Argument of type 'string[]' is not assignable to parameter of type 'string'.

i found anwser. Three dots # vs arguments. i change ngOnInit(): void { if(this.check('string1')){} } — ngaotruyen
– ngaotruyen, Commented May 31, 2022 at 9:58
If you found the solution please accept one of the answers or post your own answer to close the issue, do not hide the solution in the comments. — CrystalSpider
– CrystalSpider, Commented May 31, 2022 at 10:02

CrystalSpider · Accepted Answer · 2022-05-31 09:58:11Z

0

You should change your code into:

let req:string[] = ['string1'];
if(this.check(...req)){}

Or

let req = 'string1';
if(this.check(req)){}

answered May 31, 2022 at 9:58

CrystalSpider

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Comments

ebarooni · Accepted Answer · 2022-05-31 10:05:46Z

0

Can you please share the code of this._RolesService.checkRoles(request)? I think this function accepts a string as parameter, but you are passing ['string1'] which is an array of string. That is why the error is thrown.

Based on the current info you have provided, I think this is the issue.

Corrected solution: Thanks to the comments under this solution, one of the ways to solve your issue is to use the spread operator when calling the method:

this.check(...req)

edited May 31, 2022 at 10:05

answered May 31, 2022 at 9:51

ebarooni

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3 Comments

ngaotruyen Over a year ago

public check(roles: string[]): boolean { var userRole = this._AuthenticationService.currentUserValue.userRole; return userRole?.some(e => roles?.includes(e.role.code +"")); }

ngaotruyen Over a year ago

I think "three dots" inside function check.

Eliseo Over a year ago

The spread operator inside a function is when you call to the function with parameters. typical sum(...values:number[]), and you use sum(1,2,3,4). -see you call to the function with a number of parameters -in the e.g. 4-. You can see as "rest of parameters", see, e.g. this link. In your example works if you call to the function like:this.check('string1')

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