oop - Unable to create typescript class object -

new typescript, came across typescript class following.

export class errors {     errors: { [key: string]: string } = {}; } 

i trying create error object manually. can show usage of this? tried following.

errlist: errors = new errors();  errlist = {'key':'value'};  errlist = [       {         key: "code1",         value: "err1"       },       {         key: "code2",         value: "err2"       },     ]  errlist.errors = {     [key1]:"myvaluex" , [key3]:"myvaluey" }; 

to initialize class declared have use :

var err = new errors(); err.errors = {     "key": "value" }; 

another alternative define constructor initialize this:

export class errors {     constructor(public errors: { [key: string]: string } = {}){}; }  var err = new errors({     "key": "value" }); 

if not have errors on class use interface instead , wouldn't need constructor , use object literals initialize:

export interface  errors {     errors: { [key: string]: string }; }  var err: errors = {     errors: {  "key": "value" } }; 

which 1 choose matter of preference , use case. go constructor version, concise initialize lets use instanceof operator, interface version not.