gopherjs - xjs/xjs.go

     1  // Package xjs provides some simple, but often needed shortcut funcs for gopherJS
     2  package xjs // import "vimagination.zapto.org/gopherjs/xjs"
     3  
     4  import (
     5  	"fmt"
     6  	"strings"
     7  
     8  	"github.com/gopherjs/gopherjs/js"
     9  
    10  	"honnef.co/go/js/dom"
    11  )
    12  
    13  // body var used to cache the wrapped body once Body is sucessfully called
    14  var body *dom.HTMLBodyElement
    15  
    16  // Body gets the document's body element
    17  func Body() *dom.HTMLBodyElement {
    18  	if body == nil {
    19  		o := js.Global.Get("document").Get("body")
    20  		if o == nil || o == js.Undefined {
    21  			return nil
    22  		}
    23  		body = &dom.HTMLBodyElement{BasicHTMLElement: &dom.BasicHTMLElement{&dom.BasicElement{&dom.BasicNode{js.Global.Get("document").Get("body")}}}}
    24  	}
    25  	return body
    26  }
    27  
    28  // RemoveChildren removes all of the child nodes of the node given
    29  func RemoveChildren(node dom.Node) dom.Node {
    30  	n := node.Underlying()
    31  	for n.Call("hasChildNodes").Bool() {
    32  		n.Call("removeChild", n.Get("lastChild"))
    33  	}
    34  	return node
    35  }
    36  
    37  // SetInnerText removes all child nodes from the given node and sets a single
    38  // Text Node with the given string
    39  func SetInnerText(node dom.Node, text string) dom.Node {
    40  	n := node.Underlying()
    41  	for n.Call("hasChildNodes").Bool() {
    42  		n.Call("removeChild", n.Get("lastChild"))
    43  	}
    44  	n.Call("appendChild", js.Global.Get("document").Call("createTextNode", text))
    45  	return node
    46  }
    47  
    48  // SetPreText does similar to SetInnerText, but linebreaks are converted to <br />s
    49  func SetPreText(node dom.Node, text string) dom.Node {
    50  	n := node.Underlying()
    51  	for n.Call("hasChildNodes").Bool() {
    52  		n.Call("removeChild", n.Get("lastChild"))
    53  	}
    54  	for i, part := range strings.Split(text, "\n") {
    55  		if i > 0 {
    56  			n.Call("appendChild", js.Global.Get("document").Call("createElement", "br"))
    57  		}
    58  		n.Call("appendChild", js.Global.Get("document").Call("createTextNode", part))
    59  	}
    60  	return node
    61  }
    62  
    63  // CreateElement is a shortcut to create an element with the given name
    64  func CreateElement(name string) dom.Element {
    65  	return dom.WrapElement(js.Global.Get("document").Call("createElement", name))
    66  }
    67  
    68  // Alert provides for formated alert boxes
    69  func Alert(format string, params ...interface{}) {
    70  	js.Global.Call("alert", fmt.Sprintf(format, params...))
    71  }
    72  
    73  // Text creates a text node containing the givin text
    74  func Text(text string) *dom.Text {
    75  	return &dom.Text{&dom.BasicNode{js.Global.Get("document").Call("createTextNode", text)}}
    76  }
    77  
    78  // AppendChildren appends all the given children to the parent.
    79  func AppendChildren(parent dom.Node, children ...dom.Node) dom.Node {
    80  	for _, child := range children {
    81  		parent.AppendChild(child)
    82  	}
    83  	return parent
    84  }
    85  
    86  // Log prints a formatted string to the javascript console
    87  func Log(format string, params ...interface{}) {
    88  	js.Global.Get("console").Call("log", fmt.Sprintf(format, params...))
    89  }