Unexpected keyword 'const'. Const declarations are not supported in strict mode. about abc2svg

[moinejf]

I fixed the 'const' problem. May you check if playing works now?

About play.js, it seems hard to make it work out of its context, i.e. web browser, abc2svg core and ABC extraction (abcemb.js). Which usage are you thinking about?

[joaocc]

Hi @moinejf.
We are also trying to use abc2svg in a webpage context and we also found some problem with "strict". In case you are interested, we have setup an example at https://github.com/highskillz/ng-xml2abc2svg/commit/4e86bd8e4824eead15445cfb369a7ba2b39d6739 .
Thanks!

[moinejf]

Hi @jaocc,
Your link points to the commit, but I could not find any example.
May you give me more information about the problem?

[joaocc]

Sorry about the hurried post. Should have made this clearer.

That example is a test to using abc2svg in an Angular4 environment.

In that repo, in the 2 most recent commits, we have tried to update the version of the library to 1.13.1.
When running the version on commit 0a112b3 we have an error (https://i.imgur.com/S1dffDx.png).
By removing the "strict" directive (commit 4e86bd8 the code starts working again.

Hope this helps

[moinejf]

The error image is not clear to me. It says:
"ReferenceError: Abc is not defined"
but I can't see the code that raises this error.
Also, I don't know about a file 'abc2svg.ts' and there is no 'new Abc2svg' in my code.

In my 'abc2svg-1.js', "use strict" is at the head of the file. So, if you appended some other file(s) to this one, the mode will be extended to the added file(s), and, then, the error may appear in these ones.

But, normally, with a dynamic load (as it should be), such a problem would not occur.

[Ralex86]

'Use strict' is essential for me as I am using React (and not angular) and this library only allows you strict mode as it is a good practice. As I said everything works fine for me when replacing const by var.

About the usage of play-1.js I was think about this scenario :
I have a string with all the abc data needed (header + abc music notation + \n at the end of each line)

I am using this function as mentioned in the core tutorial you used to provide on your webpage
convert(src, callback){ var errtxt = "", new_page = "" var user = { img_out: function(str){ this.svg = ((typeof this.svg === 'undefined') ? "" : this.svg + '\n') + str if (str == "</div>") callback(this.svg) }, errmsg: function(msg,l,c){ errtxt += msg + '\n' console.log(errtxt) console.log('line, column', l, c) }, page_format: true } var abc = new Abc(user) abc.tosvg("a", src) }

Then instead of adding the svg in my database I want to store the output into a var I could use later (DOM insertion) :

this.src = X: ${result[i].id}\n+T: ${result[i].T.split('\n')[0]}\n+R: ${result[i].R}\n+ M: ${result[i].M}\n+ K: ${result[i].K}\n+${result[i].body}\n`

                this.convert(this.src, (svg) => {
                    var insert = `INSERT INTO ${this.dest_table} (tuneID, svg) VALUES (
                    ${result[i].id}, 
                    "${this.mysql_real_escape_string(svg)}")`
                    
                    this.connection.query(insert, (err, result) => {
                        if (err) throw err
                        console.log("1 record inserted")
                    })
                }) // convert`

I wish I could do the same with play-1.js. Having the midi output stored somewhere, somehow and using it with a midi player.

Here is a node script exemple using your api : https://github.com/Ralex86/Tunesbook-backend/blob/master/utils/sheet2database.js

[Ralex86]

Ok seems as I am using template string in the code above Github code insertion is having a bad time

[moinejf]

@Ralex86
(sorry for I did not understand your last message)
About MIDI, play-1.js does not output MIDI. Actually, it contains 2 parts:

• the generation of notes from the parsed ABC
• playing the notes through HTML5 audio

For MIDI generation, only the code of the first part, i.e. the function add(), is useful.
This one has to be called from (or as) the user.get_model callback function.
It creates an array (a_e) of the notes to be played. Then, this array could be used to generate a MIDI file.

I will have a look for splitting the script play.js into two different scripts. Then, the note generation script could be used in both the browser and shell contexts.

Is this OK for you?

[moinejf]

'const' removed everywhere. Last commit: 738c173
Also, audio generation has been splitted into generic and HTML5 audio scripts by the commit a5ad5d9

[joaocc]

@moinejf It seems that "use script" still causes problems (uploaded for test under https://github.com/highskillz/ng-xml2abc2svg). Do you prefer we open a separate issue? Thx

[moinejf]

@joaocc I still think that the problem is on your side, and, also, it could not occur if you use require().
But, anyway, I will move "use strict" inside the Abc object.

[joaocc]

Thanks for the fix and update.
Regarding your question, it is possible to use require, but we have been trying to follow what seems to be the standard way of importing modules in an Electron+WebPack+Angular4. We can look into it if you later decide to revert the decision.