Updating cut to support more configurations, fixes #34

src/replace-words.js

@@ -230,7 +230,7 @@ function replaceExceptions(options) {
 
 /* Replaces cut statements with cuts */
 function replaceCuts() {
-  const searchTerm = /cut\/([^\/]+)\/(-?[\d]+)\//i;
+  const searchTerm = /cut\/([^\/]+)\/(-?[\d]+)\/(?:(-?[\d]+)\/)?/i;
   walk(document.body, searchTerm, null, cutMethod);
 }
 
@@ -360,26 +360,41 @@ function exceptionMethod(node, searchTerm, options) {
   exceptionMethod(node, searchTerm, options);
 }
 
-/* Allows for custom words to be cut off */
+/* Allows for custom words to be truncated */
 function cutMethod(node, searchTerm, unused) {
   const match = node.nodeValue.match(searchTerm);
   if (match == null) { return; }
   const target = match[1];
-  const amount = match[2];
+  let start = Number(match[2]);
+  let end = Number(match[3]);
 
-  if (target.length <= Math.abs(amount)) {
-    node.nodeValue = node.nodeValue.replace(searchTerm, target);
-    cutMethod(node, searchTerm, unused);
-    return;
-  }
-
-  let replaceValue;
-  if (amount < 0) {
-    replaceValue = target.slice(0, amount);
+  if (isNaN(end)) {
+    if (start < 0) { // Cut off from the right side
+      end = target.length + start;
+      start = 0;
+    } else { // Cut off from the left side
+      end = target.length;
+    }
   } else {
-    replaceValue = target.slice(amount);
+    const isNegStart = (start < 0) || ((start == 0) && (end < 0));
+    if (isNegStart) { // Starting from the right, move by end
+      const mod = start;
+      start = target.length + mod;
+      end = target.length + mod + end;
+    } else { // Starting from the left, move by end
+      end = start + end;
+    }
+
+    // Start should always be less than end
+    if (start > end) {
+      const greater = start;
+      start = end;
+      end = greater;
+    }
   }
 
+  const replaceValue = target.slice(start, end);
+
   node.nodeValue = node.nodeValue.replace(searchTerm, replaceValue);
   cutMethod(node, searchTerm, unused);
 }