How to use the prismjs/prism.highlight function in prismjs

sourceLines.forEach((line, index) => {

            // Trim the beginning white space depending on the index
            // and concat the source code
            source = source + line.substr(indexOfFirstChar, line.length);

            // If it's not the last line...
            if ( index !== sourceLines.length - 1 )
            {
                // Add a line break at the end
                source = source + '\n';
            }
        });

        // Generate the highlighted code
        const highlightedCode = Prism.highlight(source, Prism.languages[this.lang]);

        // Replace the innerHTML of the component with the highlighted code
        this._elementRef.nativeElement.innerHTML =
            '<pre><code class="highlight language-' + this.lang + '">' + highlightedCode + '</code></pre>';
    }
}

componentDidMount() {
    this.setState({
      parsed: highlight(this.props.code, languages.jsx, 'jsx')
    })
  }