Improve consistency of Handlebars helpers (i18n, partial, block)

[brylie]

Our Handlebars syntax uses a mixture of elements with and without spaces separating the handlebars and the prefix. E.g.

• {{_ vs. {{ _
• {{# vs. {{ #
• {{> vs. {{ >

While this does not make a difference to the Handlebars compiler, it has the following shortcomings for humans:

• it is inconsistent
• including spaces marginally reduces readability
• it has caused trouble when doing a project wide search/replace when cleaning up i18n strings

Proposal

Reformat all, or most, Handlebars code to remove spaces between the handlebars ({{) and 'prefix' (_, #, and >).

Rationale

A quick search of our code found the following counts:

• 139 results for {{>
• 22 results for {{ >

Similarly, we tend to keep the # character next to the {{ in template block helpers:

• 107 results for {{#
• 41 results for {{ #

We should prefer the first version, keeping > and # close to the {{ for these reasons:

• both cases are more common in our code, currently
• the > and # characters are a bit noisy, since they are not English words (i.e. they are more to help the computer than the developer who is reading the sourcecode)
• combining the {{> and {{# into single string, without space, makes them simpler (both to read and type)

Both the handlebars ({{) and prefixes (_, #, and >) are used primarily to help the computer (parser) to do its job.

Combining handlebars and prefixes makes it, slightly, easier for the human to read, and still accomplishes the same. I.e. {{_, {{> and {{# are easy for us to read and distinguish (without spaces), while the parser can still do its job just fine.

Quick summary

I am proposing we remove the space infix because:

• handlebars spaces are unnecessary
• handlebars spaces do not significantly increase readability (although spaces increase readability elsewhere in our code)
  • i.e. template helpers without spaces between the prefix are easy to read, since the last character is easy to distinguish
• most template helpers in our code do not separate the handlebars ({{) from the prefix (_, >, #)

[brylie]

Ping @bajiat @apinf/developers

[bajiat]

I'm ok with cleaning this, but only if it does not jeopardize finishing #1623.

[brylie]

@bajiat this seems to be a small cleanup task, just doing a 'search and replace'.

[frenchbread]

If we are going to vote, I'm 👍 for {{ > something }}, {{ _ "something" }}, {{ # something }} - "with spaces" approach.

Related discussion: #1682