How can I add keyword highlighting to JSON mode?

[tmikaeld]

I'm looking at how to highlight specific words inside JSON values, this works as a custom mode:

https://stackoverflow.com/a/43757653

But how do I apply it to the JSON mode? It seems it needs to be patched into ace/mode/text_highlight_rules.
But I can't find how to do that.

[nightwing]

You could use something like this:

"use strict";

var oop = require("../lib/oop");
var JsonHighlightRules = require("./json_highlight_rules").JsonHighlightRules;

var words = Object.create(null)
words["count"] = "keyword"
words["id"] = "keyword"
words["farm"] = "keyword"
var JsonHighlightRules2 = function() {
    JsonHighlightRules.call(this)
    // regexp must not have capturing parentheses. Use (?:) instead.
    // regexps are ordered -> the first match is used
    var i = this.$rules.start.findIndex( x=> x.token == "variable")
    this.$rules.start.splice(i, 1, { 
        token : function(value) {
            var endI = value.lastIndexOf('"')
            var word = value.slice(1, endI)
            
            return [
                {value: '"', type: "string"},
                {value: word, type: words[word] || "variable"},
                {value: value.slice(endI), type: "string"}
            ]
            
        },
        regex : '"(?:(?:\\\\.)|(?:[^"\\\\]))*?"\\s*(?=:)'
    })
    
};
   
oop.inherits(JsonHighlightRules2, JsonHighlightRules);  

exports.HighlightRules = JsonHighlightRules2;