node-red-nodes/io/ping/88-ping.html

<script type="text/html" data-template-name="ping">
    <div class="form-row" id="div-node-input-host">
        <label for="node-input-host"><i class="fa fa-dot-circle-o"></i> <span data-i18n="ping.label.target"></span></label>
        <input type="text" id="node-input-host" placeholder="192.168.0.1, www.google.com">
    </div>
    <div class="form-row">
        <label for="node-input-mode"><i class="fa fa-wrench"></i> <span data-i18n="ping.label.mode"></label>
        <select type="text" id="node-input-mode" style="width: 70%">
            <option value="timed" data-i18n="ping.label.mode_option.timed"></option>
            <option value="triggered" data-i18n="ping.label.mode_option.triggered"></option>
        </select>
    </div>
    <div class="form-row" id="div-node-input-timer">
        <label for="node-input-timer"><i class="fa fa-repeat"></i> <span data-i18n="ping.label.ping"></label>
        <input type="text" id="node-input-timer" placeholder="20">
    </div>
    <div class="form-row">
        <label for="node-input-name"><i class="fa fa-tag"></i> <span data-i18n="node-red:common.label.name"></span></label>
        <input type="text" id="node-input-name" data-i18n="[placeholder]node-red:common.label.name">
    </div>
</script>

<script type="text/javascript">

var timerParameterValidator = function(node,v){
        var mode = getMode(node)
        if(mode === "triggered"){
            return true;
        }
        if(v == ""){
            return false;
        }
        return RED.validators.number()(v);
    }
    var hostParameterValidator = function(node,v){
        var mode = getMode(node)
        if(mode === "triggered"){
            return true;
        }
        return v != ""
    }
    var getMode = function(node){
        if(node){
            return node.mode
        } else {
            let $mode = $( "#node-input-mode" );
            return $mode.val();
        }        
    }

    RED.nodes.registerType("ping",{
        category: "network-input",
        color:"#fdf0c2",
        defaults: {
            mode: {value:"timed"},
            name: {value:""},
            host: {value:"", validate: function(v){
                    return hostParameterValidator(this,v) ;
                }
            },
            timer: {value:"20", validate: function(v){
                    return timerParameterValidator(this,v) ;
                } 
            },
            inputs: {value:0}
        },
        inputs:0,
        outputs:1,
        icon: "alert.png",
        paletteLabel: function() {
            return this._("ping.ping");
        },
        label: function() {
            let lbl = this.name||this.host||this._("ping.ping");
            if(lbl.length > 20){
                lbl = lbl.substring(0,17) + "..."
            }
            return lbl;
        },
        labelStyle: function() {
            return this.name?"node_label_italic":"";
        },
        oneditprepare: function () {
            let node = this;
            let $timer = $("#div-node-input-timer");
            $("#node-input-mode").val(node.mode);
            let $mode = $( "#node-input-mode" );
            function updateControlsVisibility(){   
                node.mode = $mode.val();          
                switch (node.mode) {
                    case "triggered":
                        node.inputs = 1;
                        node._def.inputs = 1
                        $timer.hide();
                        break;
                    default:
                        node.inputs = 0;
                        node._def.inputs = 0;
                        $timer.show();
                        break;
                }
            }
            $mode.change(updateControlsVisibility);
            updateControlsVisibility();
        }
    });
</script>