To dynamically access an object's property: Use keyof typeof obj as the type of the dynamic key, e.g. type ObjectKey = keyof typeof obj; . Use bracket notation to access the object's property, e.g. obj[myVar] .
Inside the function we assign the parameters to properties in the object. To do this, we have to specify the this keyword, which refers to the calling object. The variables and parameters may have the same names. Anything we pass to the constructor as an argument, will be assigned to the property of the object.
Object.values()
is part of ES2017, and the compile error you are getting is because you need to configure TS to use the ES2017 library. You are probably using ES6 or ES5 library in your current TS configuration.
Solution: use es2017
or es2017.object
in your --lib
compiler option.
For example, using tsconfig.json
:
"compilerOptions": {
"lib": ["es2017", "dom"]
}
Note that targeting ES2017 with TypeScript does not emit polyfills in the browser for ES2017 (meaning the above solves your compile error, but you can still encounter a runtime error because the browser doesn't implement ES2017 Object.values
), it's up to you to polyfill your project code yourself if you want. And since Object.values
is not yet well supported by all browsers (at the time of this writing) you definitely want a polyfill: core-js
will do the job.
using Object.keys instead.
const data = {
a: "first",
b: "second",
};
const values = Object.keys(data).map(key => data[key]);
const commaJoinedValues = values.join(",");
console.log(commaJoinedValues);
You can use Object.values
in TypeScript by doing this (<any>Object).values(data)
if for some reason you can't update to ES7 in tsconfig.
Instead of
Object.values(myObject);
use
Object["values"](myObject);
In your example case:
const values = Object["values"](data).map(x => x.substr(0, x.length - 4));
This will hide the ts compiler error.
I have increased target in my tsconfig.json
to enable this feature in TypeScript
{
"compilerOptions": {
"target": "es2017",
......
}
}
I just hit this exact issue with Angular 6 using the CLI and workspaces to create a library using ng g library foo
.
In my case the issue was in the tsconfig.lib.json
in the library folder which did not have es2017
included in the lib
section.
Anyone stumbling across this issue with Angular 6 you just need to ensure that you update you tsconfig.lib.json
as well as your application tsconfig.json
Having my tslint
rules configuration here always replacing the line Object["values"](myObject)
with Object.values(myObject)
.
Two options if you have same issue:
(Object as any).values(myObject)
or
/*tslint:disable:no-string-literal*/
`Object["values"](myObject)`
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