CODEWITHSUNDEEP
coffeescript
Snidd
Snidd

Reputation: 187

Check if object with specific property value exists in an array

Im still trying to learn CoffeeScript, so im simply asking how you would write this code in a more simple way.

for member in draft.members
        if member.email is emailAddress then throw new Meteor.Error 500, "Cannot add member twice"

Upvotes: 3

Views: 2000

Answers (2)

epidemian
epidemian

Reputation: 19229

You can also use Array#some, which results in quite simple JS and does not require external libraries :)

emailAlreadyUsed = draft.members.some (m) -> m.email is emailAddress
throw new Meteor.Error 500, 'Cannot add member twice' if emailAlreadyUsed

Upvotes: 3

user142019
user142019

Reputation:

Step one is making it readable:

for member in draft.members
    if member.email is emailAddress
        throw new Meteor.Error 500, 'Cannot add member twice'

We can eliminate the if-expression using when:

for member in draft.members when member.email is emailAddress
    throw new Meteor.Error 500, 'Cannot add member twice'

Please don't write hideous long lines. Remember that if-expressions can span multiple lines.

As for a complete alternative, you can eliminate the for-expression if you use Underscore.js or jQuery. Here is an example using Underscore.js (if you prefer jQuery, see $.grep):

if _.find(draft.members, (m) -> m.email is emailAddress)
    throw new Meteor.Error 500, 'Cannot add member twice'

IMO, the for-expression with when is most readable.

Upvotes: 2

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