In JavaScript, .contains() and .includes() are used for different purposes:
.contains(): This is a method of the Node interface in the Document Object Model (DOM). It’s used to check whether a node is a descendant of a given node, i.e., child, grandchild, etc.
node.contains(otherNode).includes(): This is a method of the Array and String prototypes in JavaScript. It’s used to determine whether an array includes a certain value among its entries or whether a string includes a certain substring.
For arrays:
array.includes(valueToFind, fromIndex)For strings:
string.includes(searchString, position)So, the main difference is that .contains() is used with DOM nodes, while .includes() is used with arrays and strings.