Addition vs Unary Plus

Question

What does the code snippet to the right output by console.log?

There is a difference between Addition Operator(+) and Unary plus operator(+), even though they use the same '+'.

Snippet

console.log(1 + 2)
console.log(1 + + 2)
console.log(1 + + + 2)
console.log(1 + '2')
console.log(1 + + '2')
console.log('1' + 2)
console.log('1' + + 2)
console.log(1 + true)
console.log(1 + + true)
console.log('1' + true)
console.log('1' + + true)
console.log(1 + null)
console.log(1 + + null)
console.log('1' + null)
console.log('1' + + null)
console.log(1 + undefined)
console.log(1 + + undefined)
console.log('1' + undefined)
console.log('1' + + undefined)
console.log('1' + + + undefined)

Source

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