react.js mean?
<Steps progressDot current={state ? state[0] ? state[0] : null : null}
status={this.checkStatus(state ? state[1] ? state[1] : null : null)}>
......
</Steps>
react.js mean?
<Steps progressDot current={state ? state[0] ? state[0] : null : null}
status={this.checkStatus(state ? state[1] ? state[1] : null : null)}>
......
</Steps>that's probably what it means
state && state[0] ? state[0] : null is equivalent to
state? (state [0]? State [0]: null): null
MDN has a good explanation. The important point about
is that although the conditional operator is combined to the right, the order in which it is evaluated is the
ternary control character of from left to right to prevent null values. For example, data = [], wouldn't it be undefined to take data [0] directly
if (state){
if (state[0]){
return state[0]
} else {
return null
}
} else {
return null
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