To compare objects by property values, you use the following helper function: const isEqual (first, second. Second, use the array.some () method to find the searched object by property values. It only expects the this value to have a length property and integer-keyed properties. To check if an array contains an object, you follow these steps: First, create a helper function that compares two objects by their properties. If an existing, yet-unvisited element of the array is changed by callbackFn, its value passed to the callbackFn will be the value at the time that element gets visited.Changes to already-visited indexes do not cause callbackFn to be invoked on them again.callbackFn will not visit any elements added beyond the array's initial length when the call to some() began.Note, however, that the length of the array is saved before the first invocation of callbackFn. Some() does not mutate the array on which it is called, but the function provided as callbackFn can. It is not invoked for empty slots in sparse arrays. In particular, for an empty array, it returns false for any condition.ĬallbackFn is invoked only for array indexes which have assigned values. Some() acts like the "there exists" quantifier in mathematics. Otherwise, if callbackFn returns a falsy value for all elements, some() returns false. If such an element is found, some() immediately returns true and stops iterating through the array. It calls a provided callbackFn function once for each element in an array, until the callbackFn returns a truthy value. The some() method is an iterative method.
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