javascript - Why comma ' , ' and plus ' + ' log the console output in different pattern?

Question

I am using the console.log statement for debugging , but came across a scenario where using ',' or '+' with console.log statement is logging the output in different pattern.For example

(function() {
  var x = [];
  x.push({
    a: 1,
    b: 2,
  }, {
    a: 4,
    b: 3,
  }, {
    a: 5,
    b: 6
  }, {
    a: 7,
    b: 8,
  })
  console.log('Logging with , ', x);
  console.log('Logging with + ' + x);
}())

Answer 1

+(string concatenation operator) with object will call the toString method on the object and a string will be returned. So, '' + object is equivalent to object.toString(). And toString on object returns "[object Object]".

With , the object is passed as separate argument to the log method.