example of calling js from wasm ? #158

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1. MaxGraey commented on Jul 4, 2018

   

   MaxGraey

   on Jul 4, 2018

   Last edited by MaxGraey

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   Hi, Jerome.
   You can define functions inside typescript like:

   main.ts

   declare namespace console {
      function logi(val: i32);
   }
   
   // also you can do this
   @external("env", "logf")
   declare function logf(val: f64);
   
   console.logi(123);
   logf(1e10);
   
   // if you not specify this via namespace of @external decorator external will be imported 
   // with name of module i.e "main" in this case.

   On javascript side you should write something like this:

   index.js

   WebAssembly.instantiateStreaming(fetch("build/main.wasm"), {
     env: {
       // import as @external("env", "logf")
       logf(value) {
         console.log("logf: " + value);
       },
       abort(msg, file, line, column) {
         console.error("abort called at main.ts:" + line + ":" + column);
       }
     },
     console: {
       // import as console.logi
       logi(value) {
         console.log("logi: " + value);
       }
     }
   }).then(result => {
     // const exports = result.instance.exports
   });

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2. MaxGraey commented on Jul 4, 2018

   

   MaxGraey

   on Jul 4, 2018

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   Arguments which can be passed between JS <-> WASM is pretty limit it's just i32 and f64. For passing strings, arrays and etc you can use this package
3. MaxGraey commented on Jul 5, 2018

   

   MaxGraey

   on Jul 5, 2018

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   By the way after approved this PR AssemblyScript in WebAssembly Studio works again
4. dcodeIO

   added

   question

   on Jul 10, 2018
5. dcodeIO commented on Oct 27, 2018

   

   dcodeIO

   on Oct 27, 2018

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   Closing this issue for now as it hasn't received any replies recently. Feel free to reopen it if necessary!
6. dcodeIO

   closed this as completedon Oct 27, 2018
7. trusktr commented on May 27, 2019

   

   trusktr

   on May 27, 2019

   Last edited by trusktr

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   For the life of me, I can't figure this out (well, short of diving into the AssemblyScript source code). I posted more details in #384

   EDIT: As described in #384, I resorted to using @external syntax, and placed that in a separate file so as not to taint the other files with non-portable syntax.
8. PaperPrototype commented on Nov 17, 2025

   

   PaperPrototype

   on Nov 17, 2025

   Last edited by PaperPrototype

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   for a scripting playground do I have the user specify externs or is there a way to not need to declare them but instead have them simply exist in the global scope?

   Or I guess in other words how do I instantiate the standard library. Maybe I could manually add the declare before the user code with string combine?