javascript includes() case insensitive

I have an array of strings that I need to loop and check against with another passed in string.

var filterstrings = ['firststring','secondstring','thridstring']; var passedinstring = localStorage.getItem("passedinstring"); for (i = 0; i < filterstrings.lines.length; i++) { if (passedinstring.includes(filterstrings[i])) { alert("string detected"); } } 

How do I ensure that case sensitivity is ignored here (preferably by using regex) when filtering, if the var passedinstring were to have strings like FirsTsTriNg or fiRSTStrING?

10 Answers

You can create a RegExp from filterstrings first

var filterstrings = ['firststring','secondstring','thridstring']; var regex = new RegExp( filterstrings.join( "|" ), "i"); 

then test if the passedinstring is there

var isAvailable = regex.test( passedinstring ); 

You can simply convert the passedinstring to lowercase.

var passedinstring = localStorage.getItem("passedinstring").toLowerCase(); 

ES6 array method filter() can simplify the solution to a single line. Use includes() method to determine whether an array includes a certain value among its entries in conjunction to the toLowerCase() method to convert it to lowercase.

var filterstrings = ['firststring','secondstring','thridstring']; var passedinstring = localStorage.getItem("passedinstring"); // convert each string from filterstrings and passedinstring to lowercase // to avoid case sensitive issue. filteredStrings = filterstrings.filter((str) => str.toLowerCase().includes(passedinstring.toLowerCase()) 

convert filterstring and passedinstring to lowercase and compare

var filterstrings = ['firststring','secondstring','thridstring']; var passedinstring = localStorage.getItem("passedinstring").toLowerCase(); for (i = 0; i < filterstrings.lines.length; i++) { if (passedinstring.includes(filterstrings[i].toLowerCase())) { alert("string detected"); } } 

You can switch .includes with the .some method which returns a boolean.
It will exit as soon as a match was found, which is great for performance for huge arrays:

.some(item => item.toLowerCase() == lookup.toLowerCase()) 

Demo:

var arr = ['foo','bar','bar']; var lookup = "bAr"; // case-sensetive console.log( arr.includes(lookup) ) // case-insensetive without caring about the type console.log( arr.some(x => x.toLowerCase() == lookup.toLowerCase()) ) 

Or define your own Array prototype method with a unique name:

// the name ("_includes") should be unique enough not to ever be overriten // by future language updates or 3rd-party scripts Array.prototype._includes = function(target){ return this.some(x => x.toLowerCase() == (target||'').toLowerCase()) } console.log( ['foo', 'bar', 'bar']._includes("bAr") )

Fixed case sensitivity issue using toLowerCase(). It turns all the string to lower case while comparing.

var product=productList.filter((x) => x.Name.toLowerCase().includes(("Active").toLowerCase())) 

My option is comparing UPPER with UPPER or lower with lower transforming both sides (i did it often in SQL):

 var filterstrings = ['firststring','secondstring','thirDstrIng']; var passedinstring = 'ThIrDsTrInG3'; //used for of just to make it more readable for (filterstring of filterstrings) { if (passedinstring.toUpperCase().includes(filterstring.toUpperCase())) { alert("string detected"); } } 

Prompts string detected

var filterstrings = ['firststring','secondstring','thridstring']; var passedinstring = localStorage.getItem("passedinstring"); filterstrings.filter(item => item.name.toLowerCase().includes(passedinstring.toLowerCase())) 

I believe this would be simpler, shorter and more understandable.

 const q = new RegExp(query, 'i'); filteredUsers = users.filter((user: User) => { return ( user.entity.short.match(q) || user.firstname.match(q) || user.lastname.match(q) ); }); 

You can try this.

var fruits = ["Banana", "Orange", "Apple", "Mango"]; string = fruits.join(' ').toUpperCase(); // Output"BANANA ORANGE APPLE MANGO"