core/responsive-image.js
function getBreakpointSizes(element) {
  var breakpointString = element.getAttribute('data-breakpoints');

  var knownSizes = Util.map(function(s) {
    return Util.parseInteger(s);
  }, breakpointString ? breakpointString.split(',') : []);

  if (knownSizes.length <= 0) {
    return [0];
  } else {
    return Util.sortBy(knownSizes, function sortAscending(a, b) {
      return b - a;
    });
  }
}
function getBreakpointSizes(element) {
  var breakpointString = element.getAttribute('data-breakpoints');

  var knownSizes = Util.map(function(s) {
    return Util.parseInteger(s);
  }, breakpointString ? breakpointString.split(',') : []);

  if (knownSizes.length <= 0) {
    return [0];
  } else {
    return Util.sortBy(knownSizes, function sortAscending(a, b) {
      return b - a;
    });
  }
}
function getBreakpointSizes ( element ) { var breakpointString = element . getAttribute ( 'data-breakpoints' ) ; var knownSizes = Util . map ( function ( s ) { return Util . parseInteger ( s ) ; } , breakpointString ? breakpointString . split ( ',' ) : [ ] ) ; if ( knownSizes . length <= 0 ) { return [ 0 ] ; } else { return Util . sortBy ( knownSizes , function sortAscending ( a , b ) { return b - a ; } ) ; } }
Parse the breakpoints = require(the `data-breakpoints` attribute.
@param {Element} element The source element.
@return {Array} Sorted array of known sizes.
Parse the breakpoints = require ( the data - breakpoints attribute .