github.com/guyezi/gofrontend@v0.0.0-20200228202240-7a62a49e62c0/libgo/go/crypto/rand/rand_js.go (about)

     1  // Copyright 2018 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // +build js,wasm
     6  
     7  package rand
     8  
     9  import "syscall/js"
    10  
    11  func init() {
    12  	Reader = &reader{}
    13  }
    14  
    15  var jsCrypto = js.Global().Get("crypto")
    16  var uint8Array = js.Global().Get("Uint8Array")
    17  
    18  // reader implements a pseudorandom generator
    19  // using JavaScript crypto.getRandomValues method.
    20  // See https://developer.mozilla.org/en-US/docs/Web/API/Crypto/getRandomValues.
    21  type reader struct{}
    22  
    23  func (r *reader) Read(b []byte) (int, error) {
    24  	a := uint8Array.New(len(b))
    25  	jsCrypto.Call("getRandomValues", a)
    26  	js.CopyBytesToGo(b, a)
    27  	return len(b), nil
    28  }