If not empty or null in JS return function

Question

I have Javascript function and I want to check multiple if statements in return.

If the value exist or is not null then it should return a row with information,

I am not sure how to do this, I am thinking something like this, E.g:

function format(d){
    return '<table cellpadding="5" cellspacing="0" border="0">' +
    if (name) {
     '<tr>' +
         '<td>Name:</td>' +
         '<td>' + d.name + '</td>' +
     '</tr>' } +
     if (place)
     '<tr>' +
         '<td>Place:</td>' +
         '<td>' + d.place + '</td>' +
     '</tr>' } +
     if (date) {
     '<tr>' +
         '<td>Date:</td>' +
         '<td>' + d.date + '</td>' +
     '</tr>' } +
    '</table>'; 
}

you can't do that with if - its not an expression - you could youse ternary but thats messy - consider using building the string on your way out — Daniel A. White
– Daniel A. White, Commented Feb 5, 2021 at 0:35

Joundill · Accepted Answer · 2021-02-05 02:36:08Z

2

Like Daniel pointed out, you could build the string on your way out like this:

function  myFormat(d) {
      let result = '<table cellpadding="5" cellspacing="0" border="0">';
      if (name){
        result += '<tr>' + '<td>Name:</td>' + '<td>' + d.name + '</td>' + '</tr>';
      }
      if (place){
        result += '<tr>' + '<td>Place:</td>' + '<td>' + d.place + '</td>' + '</tr>'; 
      }
      if (date){
        result += '<tr>' + '<td>Date:</td>' + '<td>' + d.date + '</td>' + '</tr>'; 
      }
      result += '</table>';
      return result;
}

Html elements could be combined together as well to make it simpler like this:

'<tr><td>Place:</td><td>' + d.name + '</td></tr>'

edited Feb 5, 2021 at 2:36

Joundill

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answered Feb 5, 2021 at 0:50

BurdenKing

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Comments

jaromir · Accepted Answer · 2021-02-05 00:47:37Z

0

I see that you can create a template for row. Why not to use a separate function:

formatRow(value, label)

'formatRow' function can use if statement to check if value is empty and decide to return a row or empty string for concatenation.

function formatRow(value, label){
  if(value) {
    return '<tr>' +
         '<td>' + label + '</td>' +
         '<td>' + value + '</td>' +
     '</tr>';
  }
  return '';
}

Then run it within format() function for each property that you want to use.

answered Feb 5, 2021 at 0:47

jaromir

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Comments

Daniil Loban · Accepted Answer · 2021-02-05 01:13:18Z

function createCell(text){
  const td = document.createElement('td');
  td.textContent=text;
  return td
}

function createRow(data, key){
  row = document.createElement('tr');
  row.appendChild(createCell(key[0].toUpperCase() + key.substring(1) + ':' ))
  row.appendChild(createCell(data[key]))
  return row; 
}

function format(d){
  table = document.createElement('table');
  table.setAttribute("cellpadding", "5");
  table.setAttribute("border", "0");
  table.setAttribute("cellspacing", "0");
  Object.keys(d).forEach(key => table.appendChild(createRow(d, key)))
  return table
}

document.body.appendChild(format({data: '5 feb 2021', name: 'John', place: 'New York' }))   
document.write('<hr>')
document.body.appendChild(format({data: '5 feb 2021', name: 'John' }))   
document.write('<hr>')
document.body.appendChild(format({data: '5 feb 2021' }))

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