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diff --git a/lib/epub.js/src/mapping.js b/lib/epub.js/src/mapping.js
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+import EpubCFI from "./epubcfi";
+import { nodeBounds } from "./utils/core";
+
+/**
+ * Map text locations to CFI ranges
+ * @class
+ * @param {Layout} layout Layout to apply
+ * @param {string} [direction="ltr"] Text direction
+ * @param {string} [axis="horizontal"] vertical or horizontal axis
+ * @param {boolean} [dev] toggle developer highlighting
+ */
+class Mapping {
+	constructor(layout, direction, axis, dev=false) {
+		this.layout = layout;
+		this.horizontal = (axis === "horizontal") ? true : false;
+		this.direction = direction || "ltr";
+		this._dev = dev;
+	}
+
+	/**
+	 * Find CFI pairs for entire section at once
+	 */
+	section(view) {
+		var ranges = this.findRanges(view);
+		var map = this.rangeListToCfiList(view.section.cfiBase, ranges);
+
+		return map;
+	}
+
+	/**
+	 * Find CFI pairs for a page
+	 * @param {Contents} contents Contents from view
+	 * @param {string} cfiBase string of the base for a cfi
+	 * @param {number} start position to start at
+	 * @param {number} end position to end at
+	 */
+	page(contents, cfiBase, start, end) {
+		var root = contents && contents.document ? contents.document.body : false;
+		var result;
+
+		if (!root) {
+			return;
+		}
+
+		result = this.rangePairToCfiPair(cfiBase, {
+			start: this.findStart(root, start, end),
+			end: this.findEnd(root, start, end)
+		});
+
+		if (this._dev === true) {
+			let doc = contents.document;
+			let startRange = new EpubCFI(result.start).toRange(doc);
+			let endRange = new EpubCFI(result.end).toRange(doc);
+
+			let selection = doc.defaultView.getSelection();
+			let r = doc.createRange();
+			selection.removeAllRanges();
+			r.setStart(startRange.startContainer, startRange.startOffset);
+			r.setEnd(endRange.endContainer, endRange.endOffset);
+			selection.addRange(r);
+		}
+
+		return result;
+	}
+
+	/**
+	 * Walk a node, preforming a function on each node it finds
+	 * @private
+	 * @param {Node} root Node to walkToNode
+	 * @param {function} func walk function
+	 * @return {*} returns the result of the walk function
+	 */
+	walk(root, func) {
+		// IE11 has strange issue, if root is text node IE throws exception on
+		// calling treeWalker.nextNode(), saying
+		// Unexpected call to method or property access instead of returing null value
+		if(root && root.nodeType === Node.TEXT_NODE) {
+			return;
+		}
+		// safeFilter is required so that it can work in IE as filter is a function for IE
+		// and for other browser filter is an object.
+		var filter = {
+			acceptNode: function(node) {
+				if (node.data.trim().length > 0) {
+					return NodeFilter.FILTER_ACCEPT;
+				} else {
+					return NodeFilter.FILTER_REJECT;
+				}
+			}
+		};
+		var safeFilter = filter.acceptNode;
+		safeFilter.acceptNode = filter.acceptNode;
+
+		var treeWalker = document.createTreeWalker(root, NodeFilter.SHOW_TEXT, safeFilter, false);
+		var node;
+		var result;
+		while ((node = treeWalker.nextNode())) {
+			result = func(node);
+			if(result) break;
+		}
+
+		return result;
+	}
+
+	findRanges(view){
+		var columns = [];
+		var scrollWidth = view.contents.scrollWidth();
+		var spreads = Math.ceil( scrollWidth / this.layout.spreadWidth);
+		var count = spreads * this.layout.divisor;
+		var columnWidth = this.layout.columnWidth;
+		var gap = this.layout.gap;
+		var start, end;
+
+		for (var i = 0; i < count.pages; i++) {
+			start = (columnWidth + gap) * i;
+			end = (columnWidth * (i+1)) + (gap * i);
+			columns.push({
+				start: this.findStart(view.document.body, start, end),
+				end: this.findEnd(view.document.body, start, end)
+			});
+		}
+
+		return columns;
+	}
+
+	/**
+	 * Find Start Range
+	 * @private
+	 * @param {Node} root root node
+	 * @param {number} start position to start at
+	 * @param {number} end position to end at
+	 * @return {Range}
+	 */
+	findStart(root, start, end){
+		var stack = [root];
+		var $el;
+		var found;
+		var $prev = root;
+
+		while (stack.length) {
+
+			$el = stack.shift();
+
+			found = this.walk($el, (node) => {
+				var left, right, top, bottom;
+				var elPos;
+				var elRange;
+
+
+				elPos = nodeBounds(node);
+
+				if (this.horizontal && this.direction === "ltr") {
+
+					left = this.horizontal ? elPos.left : elPos.top;
+					right = this.horizontal ? elPos.right : elPos.bottom;
+
+					if( left >= start && left <= end ) {
+						return node;
+					} else if (right > start) {
+						return node;
+					} else {
+						$prev = node;
+						stack.push(node);
+					}
+
+				} else if (this.horizontal && this.direction === "rtl") {
+
+					left = elPos.left;
+					right = elPos.right;
+
+					if( right <= end && right >= start ) {
+						return node;
+					} else if (left < end) {
+						return node;
+					} else {
+						$prev = node;
+						stack.push(node);
+					}
+
+				} else {
+
+					top = elPos.top;
+					bottom = elPos.bottom;
+
+					if( top >= start && top <= end ) {
+						return node;
+					} else if (bottom > start) {
+						return node;
+					} else {
+						$prev = node;
+						stack.push(node);
+					}
+
+				}
+
+
+			});
+
+			if(found) {
+				return this.findTextStartRange(found, start, end);
+			}
+
+		}
+
+		// Return last element
+		return this.findTextStartRange($prev, start, end);
+	}
+
+	/**
+	 * Find End Range
+	 * @private
+	 * @param {Node} root root node
+	 * @param {number} start position to start at
+	 * @param {number} end position to end at
+	 * @return {Range}
+	 */
+	findEnd(root, start, end){
+		var stack = [root];
+		var $el;
+		var $prev = root;
+		var found;
+
+		while (stack.length) {
+
+			$el = stack.shift();
+
+			found = this.walk($el, (node) => {
+
+				var left, right, top, bottom;
+				var elPos;
+				var elRange;
+
+				elPos = nodeBounds(node);
+
+				if (this.horizontal && this.direction === "ltr") {
+
+					left = Math.round(elPos.left);
+					right = Math.round(elPos.right);
+
+					if(left > end && $prev) {
+						return $prev;
+					} else if(right > end) {
+						return node;
+					} else {
+						$prev = node;
+						stack.push(node);
+					}
+
+				} else if (this.horizontal && this.direction === "rtl") {
+
+					left = Math.round(this.horizontal ? elPos.left : elPos.top);
+					right = Math.round(this.horizontal ? elPos.right : elPos.bottom);
+
+					if(right < start && $prev) {
+						return $prev;
+					} else if(left < start) {
+						return node;
+					} else {
+						$prev = node;
+						stack.push(node);
+					}
+
+				} else {
+
+					top = Math.round(elPos.top);
+					bottom = Math.round(elPos.bottom);
+
+					if(top > end && $prev) {
+						return $prev;
+					} else if(bottom > end) {
+						return node;
+					} else {
+						$prev = node;
+						stack.push(node);
+					}
+
+				}
+
+			});
+
+
+			if(found){
+				return this.findTextEndRange(found, start, end);
+			}
+
+		}
+
+		// end of chapter
+		return this.findTextEndRange($prev, start, end);
+	}
+
+	/**
+	 * Find Text Start Range
+	 * @private
+	 * @param {Node} root root node
+	 * @param {number} start position to start at
+	 * @param {number} end position to end at
+	 * @return {Range}
+	 */
+	findTextStartRange(node, start, end){
+		var ranges = this.splitTextNodeIntoRanges(node);
+		var range;
+		var pos;
+		var left, top, right;
+
+		for (var i = 0; i < ranges.length; i++) {
+			range = ranges[i];
+
+			pos = range.getBoundingClientRect();
+
+			if (this.horizontal && this.direction === "ltr") {
+
+				left = pos.left;
+				if( left >= start ) {
+					return range;
+				}
+
+			} else if (this.horizontal && this.direction === "rtl") {
+
+				right = pos.right;
+				if( right <= end ) {
+					return range;
+				}
+
+			} else {
+
+				top = pos.top;
+				if( top >= start ) {
+					return range;
+				}
+
+			}
+
+			// prev = range;
+
+		}
+
+		return ranges[0];
+	}
+
+	/**
+	 * Find Text End Range
+	 * @private
+	 * @param {Node} root root node
+	 * @param {number} start position to start at
+	 * @param {number} end position to end at
+	 * @return {Range}
+	 */
+	findTextEndRange(node, start, end){
+		var ranges = this.splitTextNodeIntoRanges(node);
+		var prev;
+		var range;
+		var pos;
+		var left, right, top, bottom;
+
+		for (var i = 0; i < ranges.length; i++) {
+			range = ranges[i];
+
+			pos = range.getBoundingClientRect();
+
+			if (this.horizontal && this.direction === "ltr") {
+
+				left = pos.left;
+				right = pos.right;
+
+				if(left > end && prev) {
+					return prev;
+				} else if(right > end) {
+					return range;
+				}
+
+			} else if (this.horizontal && this.direction === "rtl") {
+
+				left = pos.left
+				right = pos.right;
+
+				if(right < start && prev) {
+					return prev;
+				} else if(left < start) {
+					return range;
+				}
+
+			} else {
+
+				top = pos.top;
+				bottom = pos.bottom;
+
+				if(top > end && prev) {
+					return prev;
+				} else if(bottom > end) {
+					return range;
+				}
+
+			}
+
+
+			prev = range;
+
+		}
+
+		// Ends before limit
+		return ranges[ranges.length-1];
+
+	}
+
+	/**
+	 * Split up a text node into ranges for each word
+	 * @private
+	 * @param {Node} root root node
+	 * @param {string} [_splitter] what to split on
+	 * @return {Range[]}
+	 */
+	splitTextNodeIntoRanges(node, _splitter){
+		var ranges = [];
+		var textContent = node.textContent || "";
+		var text = textContent.trim();
+		var range;
+		var doc = node.ownerDocument;
+		var splitter = _splitter || " ";
+
+		var pos = text.indexOf(splitter);
+
+		if(pos === -1 || node.nodeType != Node.TEXT_NODE) {
+			range = doc.createRange();
+			range.selectNodeContents(node);
+			return [range];
+		}
+
+		range = doc.createRange();
+		range.setStart(node, 0);
+		range.setEnd(node, pos);
+		ranges.push(range);
+		range = false;
+
+		while ( pos != -1 ) {
+
+			pos = text.indexOf(splitter, pos + 1);
+			if(pos > 0) {
+
+				if(range) {
+					range.setEnd(node, pos);
+					ranges.push(range);
+				}
+
+				range = doc.createRange();
+				range.setStart(node, pos+1);
+			}
+		}
+
+		if(range) {
+			range.setEnd(node, text.length);
+			ranges.push(range);
+		}
+
+		return ranges;
+	}
+
+
+	/**
+	 * Turn a pair of ranges into a pair of CFIs
+	 * @private
+	 * @param {string} cfiBase base string for an EpubCFI
+	 * @param {object} rangePair { start: Range, end: Range }
+	 * @return {object} { start: "epubcfi(...)", end: "epubcfi(...)" }
+	 */
+	rangePairToCfiPair(cfiBase, rangePair){
+
+		var startRange = rangePair.start;
+		var endRange = rangePair.end;
+
+		startRange.collapse(true);
+		endRange.collapse(false);
+
+		let startCfi = new EpubCFI(startRange, cfiBase).toString();
+		let endCfi = new EpubCFI(endRange, cfiBase).toString();
+
+		return {
+			start: startCfi,
+			end: endCfi
+		};
+
+	}
+
+	rangeListToCfiList(cfiBase, columns){
+		var map = [];
+		var cifPair;
+
+		for (var i = 0; i < columns.length; i++) {
+			cifPair = this.rangePairToCfiPair(cfiBase, columns[i]);
+
+			map.push(cifPair);
+
+		}
+
+		return map;
+	}
+
+	/**
+	 * Set the axis for mapping
+	 * @param {string} axis horizontal | vertical
+	 * @return {boolean} is it horizontal?
+	 */
+	axis(axis) {
+		if (axis) {
+			this.horizontal = (axis === "horizontal") ? true : false;
+		}
+		return this.horizontal;
+	}
+}
+
+export default Mapping;