mediawiki-extensions-Visual.../modules/ve/ve.Range.js
Inez Korczyński 15e0c13fa9 Create method ve.Range.isCollapsed() and added some tests for ve.Range class.
Change-Id: I866b00db196a768460b32766b82fbdf896a48fdd
2012-09-28 13:32:26 -07:00

165 lines
3.8 KiB
JavaScript

/**
* VisualEditor Range class.
*
* @copyright 2011-2012 VisualEditor Team and others; see AUTHORS.txt
* @license The MIT License (MIT); see LICENSE.txt
*/
/**
* Range of content.
*
* @class
* @constructor
* @param {Number} from Starting offset
* @param {Number} [to=from] Ending offset
* @property {Number} from Starting offset
* @property {Number} to Ending offset
* @property {Number} start Normalized starting offset
* @property {Number} end Normalized ending offset
*/
ve.Range = function veRange( from, to ) {
this.from = from || 0;
this.to = typeof to === 'undefined' ? this.from : to;
this.normalize();
};
/* Static Methods */
/**
* Creates a new ve.Range object that's a translated version of another.
*
* @method
* @param {ve.Range} range Range to base new range on
* @param {Number} distance Distance to move range by
* @returns {ve.Range} New translated range
*/
ve.Range.newFromTranslatedRange = function ( range, distance ) {
return new ve.Range( range.from + distance, range.to + distance );
};
/**
* Creates a new ve.Range object that covers all of the given ranges
*
* @method
* @param {Array} ranges Array of ve.Range objects (at least one)
* @returns {ve.Range} Range that spans all of the given ranges
*/
ve.Range.newCoveringRange = function ( ranges ) {
var minStart, maxEnd, i;
if ( !ranges || ranges.length === 0 ) {
throw new Error( 'newCoveringRange() requires at least one range' );
}
minStart = ranges[0].start;
maxEnd = ranges[0].end;
for ( i = 1; i < ranges.length; i++ ) {
if ( ranges[i].start < minStart ) {
minStart = ranges[i].start;
}
if ( ranges[i].end > maxEnd ) {
maxEnd = ranges[i].end;
}
}
return new ve.Range( minStart, maxEnd );
};
/* Methods */
/**
* Gets a clone of this object.
*
* @method
* @returns {ve.Range} Clone of range
*/
ve.Range.prototype.clone = function () {
return new ve.Range( this.from, this.to );
};
/**
* Checks if an offset is within this range.
*
* @method
* @param {Number} offset Offset to check
* @returns {Boolean} If offset is within this range
*/
ve.Range.prototype.containsOffset = function ( offset ) {
this.normalize();
return offset >= this.start && offset < this.end;
};
/**
* Gets the length of the range.
*
* @method
* @returns {Number} Length of range
*/
ve.Range.prototype.getLength = function () {
return Math.abs( this.from - this.to );
};
/**
* Sets start and end properties, ensuring start is always before end.
*
* This should always be called before using the start or end properties. Do not call this unless
* you are about to use these properties.
*
* @method
*/
ve.Range.prototype.normalize = function () {
if ( this.from < this.to ) {
this.start = this.from;
this.end = this.to;
} else {
this.start = this.to;
this.end = this.from;
}
};
/**
* Swaps from and to values, effectively changing the direction.
*
* The range will also be normalized when this is called.
*
* @method
*/
ve.Range.prototype.flip = function () {
var from = this.from;
this.from = this.to;
this.to = from;
this.normalize();
};
/**
* Determines if two Ranges are equal. Direction counts.
*
* @method
* @param {ve.Range}
* @returns {Boolean}
*/
ve.Range.prototype.equals = function ( other ) {
return this.from === other.from && this.to === other.to;
};
/**
* Creates a new ve.Range object.
*
* @method
* @param {Number} Length of the new range.
* @returns {ve.Range} A new range.
*/
ve.Range.prototype.truncate = function ( length ) {
var diff = 0;
this.normalize();
if ( this.getLength() > length ) {
diff = this.getLength() - length;
}
return new ve.Range( this.from, this.to - diff );
};
/**
* Determines if Range is collapsed or not.
* @method
* @returns {Boolean}
*/
ve.Range.prototype.isCollapsed = function () {
return this.from === this.to;
};