mw-ocg-zimwriter/lib/domutil.js

Converts mediawiki collection bundles (as generated by mw-ocg-bundler) to ZIM files

// some dom utilities, from:
// https://developer.mozilla.org/en-US/docs/Web/Guide/API/DOM/Whitespace_in_the_DOM
/* exported node_before, node_after, first_child, last_child, data_of */
"use strict";

var DomUtil = module.exports = Object.create(null);

/**
 * Throughout, whitespace is defined as one of the characters
 *  "\t" TAB \u0009
 *  "\n" LF  \u000A
 *  "\r" CR  \u000D
 *  " "  SPC \u0020
 *
 * This does not use Javascript's "\s" because that includes non-breaking
 * spaces (and also some other characters).
 */


/**
 * Determine whether a node's text content is entirely whitespace.
 *
 * @param nod  A node implementing the |CharacterData| interface (i.e.,
 *             a |Text|, |Comment|, or |CDATASection| node
 * @return     True if all of the text content of |nod| is whitespace,
 *             otherwise false.
 */
var is_all_ws = DomUtil.is_all_ws = function( nod ) {
	// Use ECMA-262 Edition 3 String and RegExp features
	return !(/[^\t\n\r ]/.test(nod.data));
};


/**
 * Determine if a node should be ignored by the iterator functions.
 *
 * @param nod  An object implementing the DOM1 |Node| interface.
 * @return     true if the node is:
 *                1) A |Text| node that is all whitespace
 *                2) A |Comment| node
 *             and otherwise false.
 */

var is_ignorable = DomUtil.is_ignorable = function( nod ) {
	return ( nod.nodeType === 8) || // A comment node
		( (nod.nodeType === 3) && is_all_ws(nod) ); // a text node, all ws
};

/**
 * Version of |previousSibling| that skips nodes that are entirely
 * whitespace or comments.  (Normally |previousSibling| is a property
 * of all DOM nodes that gives the sibling node, the node that is
 * a child of the same parent, that occurs immediately before the
 * reference node.)
 *
 * @param sib  The reference node.
 * @return     Either:
 *               1) The closest previous sibling to |sib| that is not
 *                  ignorable according to |is_ignorable|, or
 *               2) null if no such node exists.
 */
var node_before = DomUtil.node_before = function( sib ) {
	while ((sib = sib.previousSibling)) {
		if (!is_ignorable(sib)) { return sib; }
	}
	return null;
};

/**
 * Version of |nextSibling| that skips nodes that are entirely
 * whitespace or comments.
 *
 * @param sib  The reference node.
 * @return     Either:
 *               1) The closest next sibling to |sib| that is not
 *                  ignorable according to |is_ignorable|, or
 *               2) null if no such node exists.
 */
var node_after = DomUtil.node_after = function( sib ) {
	while ((sib = sib.nextSibling)) {
		if (!is_ignorable(sib)) { return sib; }
	}
	return null;
};

/**
 * Version of |lastChild| that skips nodes that are entirely
 * whitespace or comments.  (Normally |lastChild| is a property
 * of all DOM nodes that gives the last of the nodes contained
 * directly in the reference node.)
 *
 * @param sib  The reference node.
 * @return     Either:
 *               1) The last child of |sib| that is not
 *                  ignorable according to |is_ignorable|, or
 *               2) null if no such node exists.
 */
var last_child = DomUtil.last_child = function( par ) {
	var res=par.lastChild;
	while (res) {
		if (!is_ignorable(res)) { return res; }
		res = res.previousSibling;
	}
	return null;
};

/**
 * Version of |firstChild| that skips nodes that are entirely
 * whitespace and comments.
 *
 * @param sib  The reference node.
 * @return     Either:
 *               1) The first child of |sib| that is not
 *                  ignorable according to |is_ignorable|, or
 *               2) null if no such node exists.
 */
var first_child = DomUtil.first_child = function ( par ) {
	var res=par.firstChild;
	while (res) {
		if (!is_ignorable(res)) { return res; }
		res = res.nextSibling;
	}
	return null;
};

/**
 * Version of |data| that doesn't include whitespace at the beginning
 * and end and normalizes all whitespace to a single space.  (Normally
 * |data| is a property of text nodes that gives the text of the node.)
 *
 * @param txt  The text node whose data should be returned
 * @return     A string giving the contents of the text node with
 *             whitespace collapsed.
 */
var data_of = DomUtil.data_of = function ( txt ) {
	var data = txt.data;
	// Use ECMA-262 Edition 3 String and RegExp features
	data = data.replace(/[\t\n\r ]+/g, " ");
	if (data.charAt(0) === " ") {
		data = data.substring(1, data.length);
	}
	if (data.charAt(data.length - 1) === " ") {
		data = data.substring(0, data.length - 1);
	}
	return data;
};