dc.js Source: filters.js (original) (raw)

/**

• The dc.js filters are functions which are passed into crossfilter to chose which records will be
• accumulated to produce values for the charts. In the crossfilter model, any filters applied on one
• dimension will affect all the other dimensions but not that one. dc always applies a filter
• function to the dimension; the function combines multiple filters and if any of them accept a
• record, it is filtered in.
• These filter constructors are used as appropriate by the various charts to implement brushing. We
• mention below which chart uses which filter. In some cases, many instances of a filter will be added.
• Each of the dc.js filters is an object with the following properties:
• • isFiltered - a function that returns true if a value is within the filter
• • filterType - a string identifying the filter, here the name of the constructor
• Currently these filter objects are also arrays, but this is not a requirement. Custom filters
• can be used as long as they have the properties above.
• @namespace filters
• @memberof dc
• @type {{}} */ dc.filters = {};

/**

• RangedFilter is a filter which accepts keys between low and high. It is used to implement X

• axis brushing for the {@link dc.coordinateGridMixin coordinate grid charts}.

• Its filterType is 'RangedFilter'

• @name RangedFilter

• @memberof dc.filters

• @param {Number} low

• @param {Number} high

• @returns {Array}

• @constructor */ dc.filters.RangedFilter = function (low, high) { var range = new Array(low, high); range.isFiltered = function (value) { return value >= this[0] && value < this[1]; }; range.filterType = 'RangedFilter';

  return range;

};

/**

• TwoDimensionalFilter is a filter which accepts a single two-dimensional value. It is used by the

• {@link dc.heatMap heat map chart} to include particular cells as they are clicked. (Rows and columns are

• filtered by filtering all the cells in the row or column.)

• Its filterType is 'TwoDimensionalFilter'

• @name TwoDimensionalFilter

• @memberof dc.filters

• @param {Array} filter

• @returns {Array}

• @constructor */ dc.filters.TwoDimensionalFilter = function (filter) { if (filter === null) { return null; }

  var f = filter; f.isFiltered = function (value) { return value.length && value.length === f.length && value[0] === f[0] && value[1] === f[1]; }; f.filterType = 'TwoDimensionalFilter';

  return f;

};

/**

• The RangedTwoDimensionalFilter allows filtering all values which fit within a rectangular

• region. It is used by the {@link dc.scatterPlot scatter plot} to implement rectangular brushing.

• It takes two two-dimensional points in the form [[x1,y1],[x2,y2]], and normalizes them so that

• x1 <= x2 and y1 <= y2. It then returns a filter which accepts any points which are in the

• rectangular range including the lower values but excluding the higher values.

• If an array of two values are given to the RangedTwoDimensionalFilter, it interprets the values as

• two x coordinates x1 and x2 and returns a filter which accepts any points for which `x1 <= x <

• x2`.

• Its filterType is 'RangedTwoDimensionalFilter'

• @name RangedTwoDimensionalFilter

• @memberof dc.filters

• @param {Array<Array>} filter

• @returns {Array<Array>}

• @constructor */ dc.filters.RangedTwoDimensionalFilter = function (filter) { if (filter === null) { return null; }

  var f = filter; var fromBottomLeft;

  if (f[0] instanceof Array) { fromBottomLeft = [ [Math.min(filter[0][0], filter[1][0]), Math.min(filter[0][1], filter[1][1])], [Math.max(filter[0][0], filter[1][0]), Math.max(filter[0][1], filter[1][1])] ]; } else { fromBottomLeft = [[filter[0], -Infinity], [filter[1], Infinity]]; }

  f.isFiltered = function (value) { var x, y; if (value instanceof Array) { x = value[0]; y = value[1]; } else { x = value; y = fromBottomLeft[0][1]; } return x >= fromBottomLeft[0][0] && x < fromBottomLeft[1][0] && y >= fromBottomLeft[0][1] && y < fromBottomLeft[1][1]; }; f.filterType = 'RangedTwoDimensionalFilter';

  return f;

};

// ******** Sunburst Chart ********

/**

• HierarchyFilter is a filter which accepts a key path as an array. It matches any node at, or

• child of, the given path. It is used by the {@link dc.sunburstChart sunburst chart} to include particular cells and all

• their children as they are clicked.

• @name HierarchyFilter

• @memberof dc.filters

• @param {String} path

• @returns {Array}

• @constructor */ dc.filters.HierarchyFilter = function (path) { if (path === null) { return null; }

  var filter = path.slice(0); filter.isFiltered = function (value) { if (!(filter.length && value && value.length && value.length >= filter.length)) { return false; } for (var i = 0; i < filter.length; i++) { if (value[i] !== filter[i]) { return false; } } return true; }; return filter;

};