I have flask variable called 'gene_info' which is json object and I want to access one index in json for example 'gene_info['AMPH']'. 'AMPH' is a variable value in JavaScript. So how can I do this?
var symbol = 'AMPH';
var td_name = '{{ gene_info[' $symbol '] | tojson }}';
console.log(td_name);
1) Using JSON.parse
var symbol = 'AMPH';
var td_name = JSON.parse("{{ gene_info[' $symbol '] | tojson }}"); // WARN: XSS potential injection
console.log(td_name);
or 2) inline <script/>
<script>{{ gene_info[' $symbol '] | tojson }}</script>
// ...
var symbol = 'AMPH';
var td_name = window.td_name_json;
console.log(td_name);
or, the best, 3) offer it via other path
@GET
def serve_json():
import json
return json.dumps($symbol) # or jsonpickle or simplejson
if third case keep in mind you might need JavaScript's fetch or other XHR request like library (jquery, axios)
JSON.parse() because Flask's tojson outputs JSON that is a strict subset of JavaScript. You can use td_name = {{ gene_info | tojson }}; directly. You can't however use '$symbol', there is no such key in the gene_info dictionary.$symbol is also not a valid Python identifier or expression, so option 3 fails too. Returning a json.dumps() string is also not going to work, Flask has dedicated tools to produce JSON responses, please use those.tojson filter will produce is a string that's valid JSON. Where is td_name_json going to come from?
gene_infodata structure into the HTML page you generate so the JavaScript code can have access to it, or use a Python variable to select the specific entry ingene_infoto put in the page.