Buffer is not defined on generated code calling compiled

[dror1544]

I am trying to use Parser in Angular 5 (using @types/binary-parser).
In order to test the module first I use the IP header example.
when doing that I get the following error

ERROR ReferenceError: Buffer is not defined
at Parser.eval [as compiled] (eval at Parser.compile (webpack-internal:///../../../../binary-parser/lib/binary_parser.js), :3:1)
at Parser.parse (webpack-internal:///../../../../binary-parser/lib/binary_parser.js:337)
at AppComponent.parse (webpack-internal:///../../../../../src/app/app.component.ts:47)
at AppComponent.ngOnInit (webpack-internal:///../../../../../src/app/app.component.ts:21)
at checkAndUpdateDirectiveInline (webpack-internal:///../../../core/esm5/core.js:12596)
at checkAndUpdateNodeInline (webpack-internal:///../../../core/esm5/core.js:14123)
at checkAndUpdateNode (webpack-internal:///../../../core/esm5/core.js:14066)
at debugCheckAndUpdateNode (webpack-internal:///../../../core/esm5/core.js:14959)
at debugCheckDirectivesFn (webpack-internal:///../../../core/esm5/core.js:14900)
at Object.eval [as updateDirectives] (ng:///AppModule/AppComponent_Host.ngfactory.js:8)

If I call Buffer,isBuffer(buf) on my code before calling .parse() it works just fine. I removed this piece of code from binary_parser.js in function getCode and the generated code works fine.
It seems that I am missing something in the declaration of Buffer. It is included in my app.Module. so I can not put the finger on what am I missing?
This is my code as I used it:

`import { Parser } from 'binary-parser';
import { Component } from '@angular/core';
import { OnInit } from '@angular/core/src/metadata/lifecycle_hooks';
import { Buffer } from 'buffer';

@component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css']
})
export class AppComponent implements OnInit{

title = 'app';

ngOnInit(): void {
this.parse()
}
parse(){

let ipHeader = new Parser()
.endianess('big')
.bit4('version')
.bit4('headerLength')
.uint8('tos')
.uint16('packetLength')
.uint16('id')
.bit3('offset')
.bit13('fragOffset')
.uint8('ttl')
.uint8('protocol')
.uint16('checksum')
.array('src', {
    type: 'uint8',
    length: 4
})
.array('dst', {
    type: 'uint8',
    length: 4
});

const buf = new Buffer('450002c5939900002c06ef98adc24f6c850186d1', 'hex');
Buffer.isBuffer(buf);

// Parse buffer and show result
console.log(ipHeader.parse(buf));
}

}`

[jordicenzano]

+1

[riggs]

Buffer needs to be defined globally (e.g. on window) at runtime because binary-parser creates code and calls it with eval.

[jordicenzano]

Fixed with a workaround :-(

Using grunt:

'string-replace': {
            dist: {
                files: {
                    './dist/js/ABC.js': './dist/js/ABC.js'
                },
                options: {
                    replacements: [{
                        pattern: 'if (!Buffer.isBuffer(buffer)) {',
                        replacement: 'if (false) {'
                    }]
                }
            }
        },

I know is not very elegant, but it does the trick

[dror1544]

@riggs did not understand where to define the buffer.
Currently as a workaround I removed the check of isBuffer from the code but I am looking for something more elegant

`

// ctx.pushCode('if (!Buffer.isBuffer(buffer)) {');
// ctx.generateError('"argument buffer is not a Buffer object"');
// ctx.pushCode('}');

if (!this.alias) {
    this.addRawCode(ctx);
} else {
    this.addAliasedCode(ctx);`

Has anyone figured out a cleaner solution for this? I too manually comment out those 3 lines, but whenever I set up a new enlistment I need to remember doing it again.
Plus, new folks working on my project also need to know about it.

FWIW, I'm in a browser environment (Electron or Cordova) and need to polyfill Buffer (which works perfectly fine after commenting out those lines).

[Xample]

The code is ran at line 322
within this context, we just need to import and provide the Buffer object in another context.
var Buffer = require("buffer").Buffer;
this.compiled = vm.runInNewContext(src,{Buffer});
I will open a pull request