Is there a simple and efficient method to achieve the following:
const x: (string|undefined)[] = ['aaa', undefined, 'ccc'];
const y = _.filter(x, it => !!it);
in order for TypeScript to correctly identify y as string[], without needing to create a custom function for filtering? (Essentially, is there a way for the language to automatically narrow the type of a variable within, for example, an if statement when working with arrays?)
Unclear why lodash is necessary in this situation, but nevertheless:
const arr: (string|undefined)[] = ['aaa', undefined, 'ccc'];
const filteredArr = arr.filter((item): item is string => item !== undefined);
After running the filter method, filteredArr will be of type string[]. Using !!item would yield the same result, while also removing any empty string values from the array.
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