如何避免三元未定义和 boolean 检查？

Question

From this,

{[item.name]: item.value?== undefined. item:value : ''}

when value is,,, it must be

false -> {[item.name]: false}
true -> {[item.name]: true}
'str' -> {[item.name]: 'str'}
undefined -> {[item.name]: ''}

How do I avoid the ternary operator?

item.value !== undefined ? item.value : ''

item.value | '' item.value | '' fails because when value is false , it sets '' instead.

Answer 1

For modern browsers ( not IE ) there exist the Nullish coalescing operator ?? which returns the right-hand side only when the left-hand is null or undefined .

So you can do

{[item.name]: item.value ?? ''}