Actually fix detection of Backspace and Delay elements

d122bd1 attempted to fix detection of `Backspace` and `Delay` elements
by checking their `type` instead of their `type.name`

However, due to oversight, we were still performing the check with name inside
Typist.jsx.

This commit fixes that

src/Typist.jsx

@@ -114,23 +114,17 @@ export default class Typist extends Component {
   typeLine = (line, lineIdx) => {
     if (!this.mounted) { return Promise.resolve(); }
 
-    // If `line` is not a string, it is either a `Backspace` or a `Delay` element.
-    // See `extractTextFromElement`
-    const isBackspaceOrDelayElement = typeof line !== 'string';
-
     let decoratedLine = line;
     const { onLineTyped } = this.props;
 
-    if (isBackspaceOrDelayElement) {
-      if (line.type && line.type.name === 'Backspace') {
-        if (line.props.delay > 0) {
-          this.introducedDelay = line.props.delay;
-        }
-        decoratedLine = String('🔙').repeat(line.props.count);
-      } else if (line.type && line.type.name === 'Delay') {
-        this.introducedDelay = line.props.ms;
-        decoratedLine = '⏰';
+    if (utils.isBackspaceElement(line)) {
+      if (line.props.delay > 0) {
+        this.introducedDelay = line.props.delay;
       }
+      decoratedLine = String('🔙').repeat(line.props.count);
+    } else if (utils.isDelayElement(line)) {
+      this.introducedDelay = line.props.ms;
+      decoratedLine = '⏰';
     }
 
     return new Promise((resolve, reject) => {

src/utils.js

@@ -33,14 +33,22 @@ export function exclude(obj, keys) {
   return res;
 }
 
+export function isBackspaceElement(element) {
+  return element && element.type === Backspace;
+}
+
+export function isDelayElement(element) {
+  return element && element.type === Delay;
+}
+
 export function extractTextFromElement(element) {
   const stack = element ? [element] : [];
   const lines = [];
 
   while (stack.length > 0) {
     const current = stack.pop();
     if (React.isValidElement(current)) {
-      if (current.type === Backspace || current.type === Delay) {
+      if (isBackspaceElement(current) || isDelayElement(current)) {
         // If it is a `Backspace` or `Delay` element, we want to keep it in our
         // `textLines` state. These will serve as markers when updating the
         // state of the text
@@ -88,7 +96,7 @@ function cloneElementWithSpecifiedTextAtIndex(element, textLines, textIdx) {
 
   const isNonTypistElement = (
     React.isValidElement(element) &&
-    !(element.type === Delay || element.type === Backspace)
+    !(isBackspaceElement(element) || isDelayElement(element))
   );
 
   if (isNonTypistElement) {