772 set href as a required prop and as the default value for children

CHANGELOG.md

@@ -5,7 +5,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 ## [Unreleased]
 ### Changed
 - [#766](https://github.com/plotly/dash-core-components/pull/766) Update from React 16.8.6 to 16.13.0
-
+- [#776](https://github.com/plotly/dash-core-components/pull/776) Update dcc.Link to set href as children if children not defined. Makes href a required prop as well. 
 
 ## [1.8.1] -2020-02-27
 ### Added

src/components/Link.react.js

@@ -4,6 +4,8 @@ import PropTypes from 'prop-types';
 
 import React, {Component} from 'react';
 
+import {isNil} from 'ramda';
+
 /*
  * event polyfill for IE
  * https://developer.mozilla.org/en-US/docs/Web/API/CustomEvent/CustomEvent
@@ -71,7 +73,9 @@ export default class Link extends Component {
                 href={href}
                 onClick={e => this.updateLocation(e)}
             >
-                {this.props.children}
+                {isNil(this.props.children)
+                    ? this.props.href
+                    : this.props.children}
             </a>
         );
     }
@@ -87,7 +91,7 @@ Link.propTypes = {
     /**
      * The URL of a linked resource.
      */
-    href: PropTypes.string,
+    href: PropTypes.string.isRequired,
     /**
      * Controls whether or not the page will refresh when the link is clicked
      */

tests/integration/link/test_link_children.py

@@ -0,0 +1,32 @@
+import pytest
+import dash
+from dash.dependencies import Input, Output
+import dash_core_components as dcc
+import dash_html_components as html
+
+
+@pytest.mark.DCC776
+def test_lich001_default(dash_dcc):
+    app = dash.Dash(__name__)
+    app.layout = html.Div(
+        [
+            dcc.Link(id="link1", href="/page-1"),
+            dcc.Location(id="url", refresh=False),
+            html.Div(id="content")
+        ]
+    )
+    @app.callback(Output("content", "children"), [Input("link1", "children")])
+    def display_children(children):
+        return children
+
+    dash_dcc.start_server(app)
+
+    href_as_children = dash_dcc.driver.execute_script(
+        '''
+        return document.getElementById("link1").text;
+        '''
+    )
+
+    dash_dcc.wait_for_text_to_equal("#link1", "/page-1")
+
+    assert href_as_children == "/page-1"