Diffing two objects in js - checks that the new has at least the same keys as the old, and if not, shows where.

gistfile1.txt

function diffdata(legacy,shiny) {
    let delta={}
    for (const key in legacy){
        const oldval = legacy[key];
        const newval = shiny[key];
        if (typeof(oldval)==='object' && typeof(newval)==='object'){
            delta[key] = diffdata(oldval,newval)
        } else if (oldval==newval){
            delta[key]="✅";
        } else if(Math.abs((oldval-newval)/oldval)<0.001){
            delta[key]="≅";
        } else {
            delta[key]="❌ expected: "+oldval+" got: "+newval;
        }        
    }
    return delta;
}