1 files changed, 69 insertions, 0 deletions
diff --git a/packages/dev-tools-pages/ts/highlight.tsx b/packages/dev-tools-pages/ts/highlight.tsx
new file mode 100644
index 000000000..cef03904a
--- /dev/null
+++ b/packages/dev-tools-pages/ts/highlight.tsx
@@ -0,0 +1,69 @@
+import * as hljs from 'highlight.js/lib/highlight';
+import * as javascript from 'highlight.js/lib/languages/javascript';
+import * as json from 'highlight.js/lib/languages/json';
+
+hljs.registerLanguage('javascript', javascript);
+hljs.registerLanguage('json', json);
+
+interface PatchInterface {
+    [key: string]: string;
+}
+
+const PATCH_TYPES: PatchInterface = {
+    '+': 'addition',
+    '-': 'deletion',
+    '!': 'change',
+};
+
+function diffHighlight(language: string, code: any, gutter: any): string {
+    return code
+        .split(/\r?\n/g)
+        .map((line: string, index: number) => {
+            let type;
+            let currentLine = line;
+
+            if (/^-{3} [^-]+ -{4}$|^\*{3} [^*]+ \*{4}$|^@@ [^@]+ @@$/.test(currentLine)) {
+                type = 'chunk';
+            } else if (/^Index: |^[+\-*]{3}|^[*=]{5,}$/.test(currentLine)) {
+                type = 'header';
+            } else {
+                type = PATCH_TYPES[currentLine[0]] || 'null';
+                currentLine = currentLine.replace(/^[+\-! ]/, '');
+            }
+
+            const g = gutter[index];
+
+            return `<span data-gutter="${g !== undefined ? `${g}x` : ''}" class="line-${type}">${
+                hljs.highlight(language, currentLine).value
+            }</span>`;
+        })
+        .join('\n');
+}
+
+interface HighlightProps {
+    language: string;
+    code: string;
+    isDiff?: boolean;
+    gutter?: [];
+    isEtc?: boolean;
+}
+
+function highlight({ language, code, isDiff, gutter, isEtc }: HighlightProps): string {
+    if (isDiff) {
+        return diffHighlight(language, code, gutter);
+    }
+
+    const hlCode = hljs.highlight(language, code).value;
+
+    if (!isEtc) {
+        return hlCode;
+    }
+
+    const hc = hlCode.split(/\r?\n/g);
+    hc.splice(1, 0, '    ...');
+    hc.splice(hc.length - 1, 0, '    ...');
+
+    return hc.join('\n');
+}
+
+export { highlight };