Remove indexOf & textContent polyfill for IE 8 (#1645)

* Remove indexOf polyfill for IE 8

* Remove textContent polyfill for IE 8

katex.js

@@ -22,7 +22,6 @@ import {
     PathNode,
     LineNode,
 } from "./src/domTree";
-import utils from "./src/utils";
 
 import type {SettingsOptions} from "./src/Settings";
 import type {AnyParseNode} from "./src/parseNode";
@@ -42,7 +41,7 @@ let render = function(
     baseNode: Node,
     options: SettingsOptions,
 ) {
-    utils.clearNode(baseNode);
+    baseNode.textContent = "";
     const node = renderToDomTree(expression, options).toNode();
     baseNode.appendChild(node);
 };

src/functions/sizing.js

@@ -2,7 +2,6 @@
 import buildCommon from "../buildCommon";
 import defineFunction from "../defineFunction";
 import mathMLTree from "../mathMLTree";
-import utils from "../utils";
 
 import * as html from "../buildHTML";
 import * as mml from "../buildMathML";
@@ -23,7 +22,7 @@ export function sizingGroup(
     // Add size-resetting classes to the inner list and set maxFontSize
     // manually. Handle nested size changes.
     for (let i = 0; i < inner.length; i++) {
-        const pos = utils.indexOf(inner[i].classes, "sizing");
+        const pos = inner[i].classes.indexOf("sizing");
         if (pos < 0) {
             Array.prototype.push.apply(inner[i].classes,
                 options.sizingClasses(baseOptions));
@@ -69,7 +68,7 @@ defineFunction({
             type: "sizing",
             mode: parser.mode,
             // Figure out what size to use based on the list of functions above
-            size: utils.indexOf(sizeFuncs, funcName) + 1,
+            size: sizeFuncs.indexOf(funcName) + 1,
             body,
         };
     },

src/utils.js

@@ -6,32 +6,11 @@
 
 import type {AnyParseNode} from "./parseNode";
 
-/**
- * Provide an `indexOf` function which works in IE8, but defers to native if
- * possible.
- */
-const nativeIndexOf = Array.prototype.indexOf;
-const indexOf = function<T>(list: Array<T>, elem: T): number {
-    if (list == null) {
-        return -1;
-    }
-    if (nativeIndexOf && list.indexOf === nativeIndexOf) {
-        return list.indexOf(elem);
-    }
-    const l = list.length;
-    for (let i = 0; i < l; i++) {
-        if (list[i] === elem) {
-            return i;
-        }
-    }
-    return -1;
-};
-
 /**
  * Return whether an element is contained in a list
  */
 const contains = function<T>(list: Array<T>, elem: T): boolean {
-    return indexOf(list, elem) !== -1;
+    return list.indexOf(elem) !== -1;
 };
 
 /**
@@ -66,31 +45,6 @@ function escape(text: mixed): string {
     return String(text).replace(ESCAPE_REGEX, match => ESCAPE_LOOKUP[match]);
 }
 
-/**
- * A function to set the text content of a DOM element in all supported
- * browsers. Note that we don't define this if there is no document.
- */
-let setTextContent;
-if (typeof document !== "undefined") {
-    const testNode = document.createElement("span");
-    if ("textContent" in testNode) {
-        setTextContent = function(node: Node, text: string) {
-            node.textContent = text;
-        };
-    } else {
-        setTextContent = function(node: Node, text: string) {
-            node.innerText = text;
-        };
-    }
-}
-
-/**
- * A function to clear a node.
- */
-function clearNode(node: Node) {
-    setTextContent(node, "");
-}
-
 /**
  * Sometimes we want to pull out the innermost element of a group. In most
  * cases, this will just be the group itself, but when ordgroups and colors have
@@ -154,9 +108,6 @@ export default {
     deflt,
     escape,
     hyphenate,
-    indexOf,
-    setTextContent,
-    clearNode,
     getBaseElem,
     isCharacterBox,
 };