convert some React fields to ES6

- renamed empty label to placeholder

assets/js/src/form/fields/text.jsx

@@ -1,40 +1,35 @@
-define([
-  'react'
-],
-function(
-  React
-) {
-  const FormFieldText = React.createClass({
-    render: function() {
-      let value = this.props.item[this.props.field.name];
-      if(value === undefined) {
-        value = this.props.field.defaultValue || '';
-      }
+import React from 'react'
 
-      return (
-        <input
-          type="text"
-          disabled={
-            (this.props.field['disabled'] !== undefined)
-            ? this.props.field.disabled(this.props.item)
-            : false
-          }
-          className={ (this.props.field.size) ? '' : 'regular-text' }
-          size={
-            (this.props.field.size !== 'auto' && this.props.field.size > 0)
-            ? this.props.field.size
-            : false
-          }
-          name={ this.props.field.name }
-          id={ 'field_'+this.props.field.name }
-          value={ value }
-          placeholder={ this.props.field.placeholder }
-          onChange={ this.props.onValueChange }
-          {...this.props.field.validation}
-        />
-      );
+const FormFieldText = React.createClass({
+  render() {
+    let value = this.props.item[this.props.field.name];
+    if (value === undefined) {
+      value = this.props.field.defaultValue || '';
     }
-  });
 
-  return FormFieldText;
+    return (
+      <input
+        type="text"
+        disabled={
+          (this.props.field['disabled'] !== undefined)
+          ? this.props.field.disabled(this.props.item)
+          : false
+        }
+        className={ (this.props.field.size) ? '' : 'regular-text' }
+        size={
+          (this.props.field.size !== 'auto' && this.props.field.size > 0)
+          ? this.props.field.size
+          : false
+        }
+        name={ this.props.field.name }
+        id={ 'field_'+this.props.field.name }
+        value={ value }
+        placeholder={ this.props.field.placeholder }
+        onChange={ this.props.onValueChange }
+        {...this.props.field.validation}
+      />
+    );
+  }
 });
+
+module.exports = FormFieldText;