Passing a Boolean into Javascript from Flask

Question

I'm trying to use Python's Flask and Javascript to build a web map. So far I've managed to get Flask to perform an SQL query a ZIP, return some coordinates, and for the map to load that location.

Now I'm trying to control the 'visible:' part of the Javascript.

(function (w) {
var map = new ol.Map({
layers: [
         new ol.layer.Tile({
         title: 'Water color',
         visible: true,
         }),
         new ol.layer.Tile({
         title: 'OSM',
         visible: false,
         }),
        ],

        target: 'map',
        view: new ol.View({
        center: ol.proj.transform(w.latLon),
        })
    });
}(window));

Can that be done? The coordinates are passes in via w.latLon. Replacing visible: true, with visible: w.OSM and setting OSM to the string true doesn't seem to do it.

Would using 1 and 0 as Boolean substitutes work instead? — bcdan
– bcdan, Commented Jun 16, 2015 at 21:50
Nice idea, but doesn't work for me. Set as 0, 1, '0' or '1' it always behaves as true. Interesting (to a complete novice like me) how 1 and 0, when I hardcode them in, behave as true and false. — Ben Mayo
– Ben Mayo, Commented Jun 16, 2015 at 22:19
Maybe adding in an intermediate function to parse the Flask output to JavaScript and vice versa would work. — bcdan
– bcdan, Commented Jun 16, 2015 at 22:25

Ben Mayo · Accepted Answer · 2015-06-17 19:31:39Z

2

I had 2 problems. 1) I was failing to declare the variable in my template

2) I had to use this tojson device to stop it just passing a string, which is true

So, in my html template

OSM = {{ OSM|tojson }}

and in the javascript

visible : w.OSM,

answered Jun 17, 2015 at 19:31

Ben Mayo

1,3252 gold badges23 silver badges37 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

biST · Accepted Answer · 2024-02-06 17:28:27Z

0

I am a bit late but if anyone's still wondering:

visible: JSON.parse('{{ w.OSM|tojson }}');

answered Feb 6, 2024 at 17:28

biST

11 bronze badge

Collectives™ on Stack Overflow

Passing a Boolean into Javascript from Flask

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related