How to use the idyll-ast.createNode function in idyll-ast

appendNode(ast, "hello");

// $ExpectType Node[] || AST
appendNode(getNodesByName(ast, "div"), "test");

// $ExpectType Node[] || AST
appendNodes(ast, [["strong", [], ["div", ["pre", [], []]]], "test"]);

// $ExpectType Node[] || AST
prependNode(getNodesByName(ast, "div"), "test");

// $ExpectType Node[] || AST
prependNodes(ast, [["strong", [], ["div", ["pre", [], []]]], "test"]);

// $ExpectType TreeNode
createNode("div", { prop1: "prop1", prop2: ["expression", "x=2"] }, []);

// $ExpectType Node[]
getChildren(ast[0]);

// $ExpectType void
walkNodes(ast, (n: Node) => {
    (n as TreeNode)[0] = "funky-name";
});

// $ExpectType Node[]
findNodes(ast, n => n instanceof Array);

// $ExpectType Node
modifyChildren(ast[0], (n: Node) => {
    if (typeof n === "object") {
        n[0] = "somename";

function seperateTextAndHyperLink(textnode, hyperlinks) { 
  let match;                           
  let hyperLinkIndex = 0;              
  let substringIndex = 0; 
  let newChildNodes = [];           
  while(hyperLinkIndex < hyperlinks.length) {
    let regexURL = new RegExp(hyperlinks[hyperLinkIndex], "g"); 
    match = regexURL.exec(textnode.substring(substringIndex));
    if(match) {
      let linkEndIndex = regexURL.lastIndex;
      let linkStartIndex = linkEndIndex - hyperlinks[hyperLinkIndex].length;
      let textNodeValue = textnode.substring(substringIndex, linkStartIndex); 
      if(textNodeValue !== "") {
        newChildNodes.push(createTextNode(textnode.substring(substringIndex, linkStartIndex)));
      }
      let anchorElement = createNode("a", [], [hyperlinks[hyperLinkIndex]]); 
      setProperty(anchorElement, "href", hyperlinks[hyperLinkIndex]);
      newChildNodes.push(anchorElement); 
      textnode = textnode.substring(linkEndIndex);
      substringIndex = 0;   
    }
    hyperLinkIndex++;
  }
  if(textnode != "") {
    newChildNodes.push(createTextNode(textnode)); 
  }
  return createNode("span", [], newChildNodes); 
}

let textNodeValue = textnode.substring(substringIndex, linkStartIndex); 
      if(textNodeValue !== "") {
        newChildNodes.push(createTextNode(textnode.substring(substringIndex, linkStartIndex)));
      }
      let anchorElement = createNode("a", [], [hyperlinks[hyperLinkIndex]]); 
      setProperty(anchorElement, "href", hyperlinks[hyperLinkIndex]);
      newChildNodes.push(anchorElement); 
      textnode = textnode.substring(linkEndIndex);
      substringIndex = 0;   
    }
    hyperLinkIndex++;
  }
  if(textnode != "") {
    newChildNodes.push(createTextNode(textnode)); 
  }
  return createNode("span", [], newChildNodes); 
}