Function to highlight user input inside autosuggest component

.js

highlightWords = (string, highlight) => {
        let counter = 0;
        let str = string;
        let index = string.toLowerCase().indexOf(highlight.toLowerCase());
        let result = [];

        while(index > -1) {
            result.push(<span key={counter++}>{str.slice(0, index)}</span>);
            result.push(<mark key={counter++}>{str.slice(index, index + highlight.length)}</mark>);
            str = str.slice(index + highlight.length);
            index = str.toLowerCase().indexOf(highlight.toLowerCase());
        }

        result.push(<span key={counter++}>{str}</span>);

        return result;
    };