title: pdfMake pageBreakBefore feature is not working
body: <p>I am trying to concatenate multiple pdf files to a content variable.   However I want each pdf content to be on a new page,  but pdfmake.js just concatenate each content right after the other.   I have added 'pageBreakBefore' function right after my content but it still doesn't work.   Is there a way to make each content to be on separate page.   (I am using jpdmake.js 1.60).   Thanks!</p>
  <p>Below is my code:</p>
  <pre><code>        let content = [];
          content = this.getContent(checkedOrders, selectedLabOrders);
          this.docDefinition = {
                        info: {
                          title: 'Title',
                          subject: 'labOrder-' 
                        },
                        pageSize: 'LETTER',
                        pageOrientation: 'landscape',
                        pageMargins: [40, 30, 40, 30],
          
                        content: content,
                        pageBreakBefore: function(currentNode, followingNodesOnPage, nodesOnNextPage, previousNodesOnPage) {
                          return currentNode.headlineLevel === 1 &amp;&amp; followingNodesOnPage.length === 0;
                        },
                        unbreakable: true,
                        styles: {
                          titleHeader: {
                            fontSize: 16,
                            bold: true,
                            margin: [0, 10, 0, 0],
                          },
                          tableHeader: {
                            bold: true,
                            fontSize: 13,
                            color: 'black'
                          }
                        },
                        defaultStyle: {
                          fontSize: 9,
                          lineHeight: .9
                        }
                      };
  </code></pre>
  <p><a href="https://i.stack.imgur.com/lU7OJ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/lU7OJ.png" alt="enter image description here" /></a></p>