Typescript class not accepting argument type

Question

I'm creating new classes in Angular for data model.

I have created classes in new file and initialize them ins constructor

export class CreditPoliciesDetails { 
    private _fileName : string ="" ;
    private _fileDate : string ="" ;
    private _fileSize : string ="" ;
    private _path : string=""; 
    private _extention: string="";
    constructor() {
        this._fileDate="fileDate";
        this._fileName="fileName";
        this._fileSize="fileSize";
        this._path="path";
        this._extention="extension";
    }
}  

export class CreditPolicies {
    private _document : CreditPoliciesDetails[];
    private _directory: string
    constructor (details: CreditPoliciesDetails[]) {
        this._document = details;
        this._directory="";
    }
    get category() {
        return this._document
    }
    public details (detail) {
        console.log(detail)

        this._document= detail;
    }
}

Then in my component ts file I declare new CreditPoliciesDetails array then pass it to files which is an array of type of CreditPolicies

  details :CreditPoliciesDetails[] = new Array <CreditPoliciesDetails>(); 

  files : CreditPolicies[] = new Array <CreditPolicies>(this.details);

In VS code I get a warning When I hover the argument of new Array <CreditPolicies>(this.details); Argument of type 'CreditPoliciesDetails[]' is not assignable to parameter of type 'CreditPolicies'. Property '_document' is missing in type 'CreditPoliciesDetails[]'.

And when I console.log files and details I get empty array.

I'm expecting this format

[  
   {  
      "directory":"string",
      "document":[{  
         "extension":"string",
         "lastModifiedDate":"string",
         "name":"string",
         "path":"string",
         "size":"0"
      }]
   }
]

details is empty array in your case. You're providing empty array as new Array argument, while it's expected to be a number - and will result in empty files array too. I'd suggest to check how arrays work in JS, because they work in TS exactly the same way. — Estus Flask
– Estus Flask, Commented Apr 19, 2018 at 9:23

mastermind · Accepted Answer · 2018-04-19 09:24:30Z

1

You have to call the constructor, not to cast the CreditPoliciesDetails array into CreditPolicies array

details :CreditPoliciesDetails[] = new Array <CreditPoliciesDetails>(); 

//files : CreditPolicies[] = new Array <CreditPolicies>(this.details);

files : CreditPolicies = new CreditPolicies(this.details);

answered Apr 19, 2018 at 9:24

mastermind

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5 Comments

infodev Over a year ago

Files should be an array like in the expected format. How can I call the constructor for details and files and declaring them as arrays in the same time ?

mastermind Over a year ago

what u can do is declare the array first, then initialize it 1 by 1 in an loop or so by calling the constructor

mastermind Over a year ago

i think u r confused in structure some where, What i understand from the code is u have 1 file**(CreditPolicy) can have multiple **details(CreditPolicyDetails). if its true then its OK. means u have details :CreditPoliciesDetails[] = new Array <CreditPoliciesDetails>(); contains the details of 1 FILE

mastermind Over a year ago

other situation is 1 detail have 1 file. means details :CreditPoliciesDetails[] = new Array <CreditPoliciesDetails>(); having 5 details and we want 5 files (CreditPolicy) then this is something else

infodev Over a year ago

Files is an Array of CreditPolicies and every _document could have n detail. for example : we have many directories , and every directory contain many files..

Petr Borák · Accepted Answer · 2018-04-20 15:11:23Z

0

(this.details); Argument of type 'CreditPoliciesDetails[]' is not assignable to parameter of type 'CreditPolicies'.

It simply says, that you have in the

this.details

an arrray of the type CreditPoliciesDetails, that you are trying to pass to the constructor. Array used as a constructor in this case, expects arguments of type CreditPolicies. You are passing an array of CreditPoliciesDetails.

Also, I recomend using the following syntax for the previous code.

export class CreditPoliciesDetails { 
    constructor(
        private _fileDate="fileDate",
        private _fileName="fileName",
        private fileSize="fileSize";.....

) {}
}

It spares time and makes the code more eligible.

edited Apr 20, 2018 at 15:11

answered Apr 19, 2018 at 9:30

Petr Borák

564 bronze badges

2 Comments

infodev Over a year ago

I havn't understand this part Array used as constructor expects single values as parametres.

Petr Borák Over a year ago

Array used as a constructor in this case, expects arguments of type CreditPolicies. You are passing an array of CreditPoliciesDetails.

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