Learning Destructuring assignment in Javascript and when trying to have an array in object destructuring, just first letter return to console, why it's happening?
function splitter(name) { const [fName, lName] = name.split(" "); return { fName, lName }; } const {fName: [firstWord],lName} = splitter("John Doe"); console.log(splitter("John Doe")); console.log({fName: [firstWord],lName}); console.log(firstWord); console.log(lName);
Let's first take the simple case, where you are just destructuring the array
function splitter(name) { const [fName, lName] = name.split(' '); return { fName, lName }; } const { fName, lName } = splitter('John Doe'); console.log(fName); // John
Remember the
strings
are iterable in JS
const str = 'John'; for (let c of str) { // For-of can only be used in iterables console.log(c); }
So when you do
const { fName: [firstWord], lName } = splitter('John Doe');
then this means you are also destructuring from the fName
string, which will result in the firstChar
as
So the above is exactly same as:
const { fName, lName } = splitter('John Doe');
const [firstChar] = fName;
console.log(firstChar);
function splitter(name) { const [fName, lName] = name.split(' '); return { fName, lName }; } const { fName, lName } = splitter('John Doe'); const [firstChar] = fName; console.log(firstChar);
This happen because splitter
returns you fName
and lName
, each of them is a word, string, which is an array of characters.
When you restructure fName
to an array, it gives you the first letter in the array.
If you will add more args to the array you will get the rest of the letters.
To fix your issue just don't restructure into an array.
function splitter(name) { const [fName, lName] = name.split(" "); return { fName, lName }; } const {fName: [ch1,ch2,ch3,ch4],lName} = splitter("John Doe"); console.log({fName: [ch1,ch2,ch3,ch4],lName}); const {fName: [char1, ...restOfChars]} = splitter("John Doe"); console.log(char1); console.log(restOfChars); const {fName: wholeWord} = splitter("John Doe"); console.log(wholeWord);
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