The JavaScript Symbol.isConcatSpreadable property determines if an object should be flattened to its array elements or not.
Syntax:
Array_name[symbol.isConcatSpredable] = true/false
Returns:
Symbol corresponding to a specific key.
Example 1:
<!DOCTYPE html> <html> <body> <script> var alpha = ['X', 'Y', 'Z']; var beta = ['A', 'B', 'C']; beta[Symbol.isConcatSpreadable] = true; var Display = alpha.concat(beta); document.write(Display); </script> </body> </html>
Example 2:
<!DOCTYPE html> <html> <body> <script> const alpha = ['d', 'e']; const numeric = [15, 52]; let alphaNumeric = alpha.concat(numeric); document.write(alphaNumeric); document.write("</br>"); numeric[Symbol.isConcatSpreadable] = true; alphaNumeric = alpha.concat(numeric); document.write(alphaNumeric); </script> </body> </html>