内联If-Else（带条件运算符）的双精度false

Question

I am trying to hide an input field if the td doesn't have a value.

I know we can have a condtition like this:

${condition ? true : false}

but how can I have an inline operator like this?

${condition ? true : false && false}

Example:

${JsonObject ? JsonObject.Description : " " && $('#textbox').removeattr("style").hide()}

The html is similar to this:

`<td>
${JsonObject ? JsonObject.Description : " " && $('#textbox').removeattr("style").hide()}
</td>
`<div><input id="textbox"></div>

Answer 1

If I'm understanding you right, you want the truthy result to be the description, and the falsy result to be " " and to have the side-effect of removing the style attribute from #textbox and hiding it.

I strongly recommend not doing that. Side-effects like that are extremely hard to debug and maintain.

But if you really want to, make the side-effect first:

`<td>
${JsonObject ? JsonObject.Description : $('#textbox').removeattr("style").hide() && " "}
</td>
`<div><input id="textbox"></div>

That works because hide returns the jQuery object, which is truthy, so the (object) && " " expression results in " " . Or as James Long points out, you could use the comma operator instead, and then the return value of hide wouldn't matter: ${JsonObject ? JsonObject.Description : ($('#textbox').removeattr("style").hide(), " ")} ${JsonObject ? JsonObject.Description : ($('#textbox').removeattr("style").hide(), " ")} (you don't actually need those () , but it's already confusing enough, and it's even more confusing without them, so...).

But again, I wouldn't. Instead, I'd just do:

`<td>
${JsonObject ? JsonObject.Description : " "}
</td>
`<div><input id="textbox"></div>

...and then just before or just after this template literal, have

if (!JsonObject) {
    $('#textbox').removeattr("style").hide();
}