CODEWITHSUNDEEP
arraystypescript
Stéphane GRILLON
Stéphane GRILLON

Reputation: 11864

Angular 2 TypeScript how to get element in Array

I need get element in a array by key.

const legendColors = {'On Hold': '#ef2e2e', 'Shipped': '#ff8e28', 'Complete': '#61c673', 'New': '#007cbb'};

...

return {name: v.name, value: v.value, color: legendColors[v.name]};

lint tool return this error on legendColors[v.name]:

ERROR in src/app/pages/orders/orders.composant.ts(46,62): error TS7017: Element implicitly has an 'any' type because type '{ 'On Hold': string; 'Shipped': string; 'Complete': string; 'New': string; }' has no index signature.

Upvotes: 1

Views: 48

Answers (1)

CRice
CRice

Reputation: 32146

Typescript complains because there is no guarantee that v.name is one of the keys of legendColors, and there is no index signature. You can get past this by giving typescript a hint that v.name is in fact one of the keys:

return {name: v.name, value: v.value, color: legendColors[v.name as keyof typeof legendColors]};

or if legendColors adheres to an interface you already know the name of, you can simplify that a little:

return {name: v.name, value: v.value, color: legendColors[v.name as keyof SomeInterface]};

Finally, if you're actually not sure if v.name is a key of legendColors, then you'll actually have to add an index signature to it.

const legendColors: {[key: string]: string} = {'On Hold': '#ef2e2e', 'Shipped': '#ff8e28', 'Complete': '#61c673', 'New': '#007cbb'};

Upvotes: 2

Related Questions