CODEWITHSUNDEEP
javascriptstringtemplatesinterpolation
sennett
sennett

Reputation: 8424

Template strings stored as constants

I have a template string:

function getTemplateString () {
  let videoId = 'qwerty'
  return `https://player.vimeo.com/video/${videoId}?api=1`
}

I want to store this template string in a const instead:

const VIMEO_EMBED_URL = `https://player.vimeo.com/video/${videoId}?api=1`

function getTemplateString () {
  let videoId = 'qwerty'
  // how can I do this next line?
  return VIMEO_EMBED_URL.something({videoId: videoId}) 
}

Can I do string interpolation on constants?

Upvotes: 1

Views: 304

Answers (2)

Andrew Willems
Andrew Willems

Reputation: 12458

Note that the back-tick quotes are nested in regular quotes.

const VIMEO_EMBED_URL = "`https://player.vimeo.com/video/${videoId}?api=1`";

function getTemplateString() {
    let videoId = 'qwerty';
    return eval(VIMEO_EMBED_URL);
}

document.write(getTemplateString());

I understand that many uses of eval, probably including this one, are not recommended. (They introduce possible security concerns, etc.) However, eval IS part of the language, and some JavaScript experts do discuss how to use it on occasion.

This answer does address the issue raised in the question and does allow the coder to combine the convenient syntax of a template string and the permanence of storing it in a const. Just understand that it's "User beware".

Upvotes: 1

carlesba
carlesba

Reputation: 3156

Template Strings cannot be stored, they return a String when they're defined. So I guess you're looking for a RegExp.

function getTemplateString (url, value) {
    return url.replace(/\${video1}/g, value)
}

Other option could be a function that applies the template:

function getTemplateString (videoId) {
    return `https://player.vimeo.com/video/${videoId}?api=1`
}

Upvotes: 2

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