A utility function to avoid type errors when traversing over arrays and object properties.
Now that optional chaining and nullish coalescing operators are available, libraries like snq have become redundant. Please use them instead.
snq is a utility function to safely navigate arrays and object properties without getting type errors. It is not an original idea at all and is actually adapted and only slightly different from idx. The main differences are as follows:
undefined
whenever a TypeError
happens, regardless of the reason for the error and throws an error only if it is not a TypeError
. idx returns null
, if the cause of the error is a null
value and throws an error if the error is not caused by an undefined
or null
value.undefined
.Run the following code in your terminal:
yarn add snq
or if you are using npm:
npm install --save snq
import snq from 'snq';
Consider the following interfaces as products
list:
interface Price {
amount: number;
currency: string;
symbol?: string;
}
interface Product {
id: number;
name: string;
inStock: boolean;
price?: {
final: Price;
original?: Price;
};
}
This is how it would probably look like when you want to get original price symbol of first product:
products.length &&
products[0].price &&
products[0].price.original &&
products[0].price.original.symbol;
Otherwise, you will get a type error. Using snq
, it is safe to write the following:
const symbol = snq(() => products[0].price.original.symbol);
// symbol is undefined if a type error happens, actual value if not
There is an optional second argument which represents the default value to return when a type error happens.
const symbol = snq(() => products[0].price.original.symbol, '$');
// symbol is "$" if a type error happens, actual value if not
The type of the symbol returned will be inferred as string in both cases.
Check the demo application out.