Converting html entities

JavaScript
#1

Hi all,
I’m wondering why my code won’t work.
It keeps converting the ‘&’ + str to the ascii characters anyway.
I tried escaping the & , tried JSON stringify , nothing seems to do it.

Hope someone can help . Thanks :slight_smile:

Your code so far


function convertHTML(str) {
let regExSymbols = /[&<>"']/g;
	let lookup = { 34:"quot;",38:"amp;",39:"apos;",60:"lt;",62:"gt;"};
	
	let matchedStrs= str.match(regExSymbols);
	for(let i=0;i<matchedStrs.length;++i){
		let index = str.search(matchedStrs[i]);
       let charcode = str.charCodeAt(index);
		let newStr = lookup[charcode];
	    str = str.replace(str.charAt(index),'&'+ newStr);
		
	}
	return str;
}

convertHTML("Dolce & Gabbana");

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:69.0) Gecko/20100101 Firefox/69.0.

Challenge: Convert HTML Entities

Link to the challenge:
https://www.freecodecamp.org/learn/javascript-algorithms-and-data-structures/intermediate-algorithm-scripting/convert-html-entities

#2

Take a look at line:
let matchedStrs= str.match(regExSymbols);
What happens if str doesn’t have any of the characters that needs converting?

#3

Thank you, good point, unfortunately it doesn’t solve my problem :slight_smile:

#4

The line referenced by @sanity is important to solving your problem. What should happen if the match method returns null? It will return null if there was no match of the characters. Do you understand what error is caused when the for loop tries to evaluate the i < matchedStrs.length condition if matchedStrs is null? If you do not, then check the browser’s console to find out.

#5

Sorry, but I have added a test for null, and the str still returns the html characters,

&lt;    returns <

I’m really confused about what you could mean then ?

#6

Can you please share your update code?

#7

Here it is :slight_smile:

let regExSymbols = /[&<>"']/g;
	let lookup = { 34:"quot;",38:"amp;",39:"apos;",60:"lt;",62:"gt;"};
	
	let matchedStrs= str.match(regExSymbols);
	if (!(matchedStrs===null)){
	    for(let i=0;i<matchedStrs.length;++i){
		   let index = str.search(matchedStrs[i]);
           let charcode = str.charCodeAt(index);
		   let newStr = lookup[charcode];
	       str = str.replace(str.charAt(index),'&'+ newStr);
		   
	    }
	}
	
	return str;
#8

You have not posted the full function code. Where is your function declaration and closing } for the function?

#9

FYI - A simpler way of writing the above is:

if (matchedStrs) {
#10

Oke my full code. I actually had the simpler (matchedStrs) first but then doubted it to be correct. It still doesn’t make a difference though:
Thank you btw :slight_smile:

function convertHTML(str) {
    let regExSymbols = /[&<>"']/g;
	let lookup = { 34:"quot;",38:"amp;",39:"apos;",60:"lt;",62:"gt;"};
	
	let matchedStrs= str.match(regExSymbols);
	if (matchedStrs){
	    for(let i=0;i<matchedStrs.length;++i){
		   let index = str.search(matchedStrs[i]);
           let charcode = str.charCodeAt(index);
		   let newStr = lookup[charcode];
	       str = str.replace(str.charAt(index),'&'+ newStr);
		   
	    }
	}
	
	return str;
}
#11

The latest code you posted passes all the tests for me. What tests are you failing? Do you see any errors showing in the browser console when you click Run Tests?

#12

I just used a document.write statement to output the tests on my laptop ide?
but it shows the html entities as html characters:

document.write(convertHTML(“Schindler’s List”)); //my laptop output: Shindler’s List

Thanks :slight_smile:

#13

If you use document.write, then the &apos; would still display as the string you originally passed to it. If you write console.log(convertHTML("Schindler's List")); and then look at your console when executing the code, you will see the conversion.

#14

Thanks . I have to remember this for future projects, I wasted a few days on this one when it was correct all along :slight_smile:

#15