Mastering Ember Js - 14 Creating and using an ember js helper Video Lecture | Build Web Applications: Ember.js - Web Development

hello everyone this is lamb it's a net
of code illogical on today's video we're
going to be having a look at how to
create and use ember.js help us
so sometimes let's just use this example
you may have some really long value in a
property name so they say we have this
property in our controller index
controller which is my very long first
name and it has some really long text
some very long name and we want that
when we output that here the help
automatically strips that out for us so
this is actually a helper in itself but
it's different from the other helpers in
that you can easily pass in an extra
helper well that's not the only
difference but it just outputs stuff but
you can pass in another help and I say
helper call strip or make shorter so we
can create a helper call make shorter
and when we pass the here that will
automatically take this as a body and
make the output shorter but before we
call that let's just see what we get by
just outputting this in the browser so
in our browser when we refresh we get
the value from the controller some very
long name but let's try to strip down to
just four let us sum okay so back in our
app to j/s let's just create a helper
and how you do that in Empire is you can
just say ember dodge handlebars
and that's a function and the first
parameter that takes is the name of the
helper and in this case we'll call it
make shorter under second parameter it
takes is a function and the function
takes two parameters that's the value
that's whatever you passed in and the
second one is an options house and we'll
get to the options part in a later video
but for this video we don't have to deal
with that so how do we deal with this so
we can we have to return whatever value
we want to be the output inside or
template so we can just say return value
dark soft string we got to start at the
zero property if you know your
JavaScript that's saying that start at
the first element and get a every
element up until the fifth
well not fifth but element at the number
five position so let's go back you know
templates and now what we do is make
sure that that will take this value here
and pass it to this helper here and then
we should get a shorter name so we go
back in our browser and we refresh we
get an error let me see what the error
is
apparently we have an undefined is not a
function okay I just realized that I
needed to switch the position basically
since this helper here is sort of a
function so think of it as you're taking
this function and you're passing this
value to it and then the output that's
what you want to see so let's go back in
the browser refresh now which will see
some F and that's just saying started 2
0 0 1 2 3 4 v 1 is not included in the
substring method for JavaScript so
that's one way of creating and the blast
helpers and if you want to get more
information about how to create help us
go to you and by J's comm guides and
there's a handlebars template section
here this is writing helpers there's
lots of information here I didn't want
to go through everything but that's just
the basics of how you create a helper in
ember.js and as you can see you can
create stuff like calendar heavens as
well and I'm not sure we're going to
leave yeah saw like an alias to view so
that's it guys thanks for watching I'll
see you in another video this was
helpful as well please do comment and
subscribe and share as well thanks for
watching bye bye