How to write Variable inside of Variable in Template String literal?

Question

log(`${chalk.magenta(' LAUNCH_COMMAND')} ${chalk.green('npm run: ')} ${chalk.red('${LAUNCH_COMMAND}')}` );

Here is the problem part: ${chalk.red('${LAUNCH_COMMAND}')}

LAUNCH_COMMAND is either 'production' or 'development'. However it's inside of another ${}.

You absolutely should not [nest template strings](https://stackoverflow.com/q/36028061/1048572) if you want to keep your own sanity, and the code's readability. — Bergi, Jul 14 '17 at 18:59

Tushar Gupta - curioustushar · Accepted Answer · 2017-07-14T19:04:55.593

3

Demo

Just use the Variable name for nested Variable in Template String literal

`${chalk.red(LAUNCH_COMMAND)}` // for nested sting literal just use the variable name

const LAUNCH_COMMAND = 'hi';
console.log(`${chalk.magenta('  LAUNCH_COMMAND')} ${chalk.green('npm run: ')} ${chalk.red(LAUNCH_COMMAND)}` );

edited Jul 14 '17 at 19:04

answered Jul 14 '17 at 18:55

Tushar Gupta - curioustushar

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trevdev · Answer 2 · 2017-07-15T05:05:30.270

-1

You don't wrap variables within string literals with quotes.

log(`${chalk.magenta(  LAUNCH_COMMAND)} ${chalk.green(npm run: )} ${chalk.red(LAUNCH_COMMAND})` );

^ Should hypothetically work though I'm not clear on the context behind why you're writing a string like this. I'm assuming it's some kind of dynamic output.

var b = "Cats"
var c = "Dogs"

function concat(one, two) {

  return `${one} and ${two}`;

}

function compare(one, two) {

  var ans = one == two ? 'Are the same' : 'Are not the same';
  return ans;

}

console.log(`${concat(b, c)} - ${compare(b, c)}`);

edited Jul 15 '17 at 05:05

answered Jul 14 '17 at 18:59

trevdev

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@Bergi Oh but it does. See my edit, added a snippet. – trevdev Jul 15 '17 at 05:05
No, try the first snippet. It produces a *SyntaxError: Invalid or unexpected token*. – Bergi Jul 15 '17 at 05:14
The first snippet wasn't meant to run, I was just referencing it. My second snippet puts the principle into practice. – trevdev Jul 15 '17 at 06:25
I appreciate it was a bad example, though. My apologies. – trevdev Jul 15 '17 at 06:31
The problem is that the parameters to `magenta` and `green` are not *supposed* to be variables. They *need* to be string literals! – Bergi Jul 15 '17 at 06:34

How to write Variable inside of Variable in Template String literal?

2 Answers2