Javascript uses {} for Object Notation.
This example illustrate how 'iterating' over the object elements (it's a dictionary!) will only get you the key and not the value.
To get the value, check the second for loop, within draw().
        var a = {
    p1: 5,
    p2: 20,
    p3: 25,
    p4: 45,
    p5: 70
};

function setup() {
    createCanvas(100, 100);
    background(240);
    for (var item in a) {
        console.log(item);
    }
}

function draw() {
    for (var v in a) {
        if (typeof a[v] !== 'function') {
            var item = a[v]
            line(0, item, 50, item);
        }
    }
}