update-map v1.0.1

Library for updating state minimally, based on changes

It is useful for using a simple state object to adjust a complex data structure or program state

const Update = require("update-map");
const dependency = [
    ["a",(scope,{a})=>{
        scope.a_val=a;
    }],
    [["b","c"],(scope,{b,c})=>{
        scope.bc_val=b+c;
    }],
    [["c"],async (scope,{c})=>{
        return new Promise(function(resolve, reject) {
            setTimeout(()=>{
                scope.c_val=true;
                resolve();
            },0);
        });
    }],
];
const scope = {
    a_val:0,
    bc_val:0,
    c_val:0,
};
const state = {
    a:1,
    b:2,
    c:3,
};
const changes = ["a","b","c"];
const updateFunc = Update(dependency);
await updateFunc(scope,changes,state);

The above code takes a set of changes and calls functions which respond to those changes

Update is the factory function for the update map function, dependency is an array of [key,value] pairs, where the key is one or more property names, and the value is a function which receives the scope object and an object whose properties are the values of state which were specified in key

for example, in the first function, this function will only be called if a was in the list of changes

scope is an object that is passed by reference and can be modified by the function

state is an object which represent the abstract representation of something

changes is an array of strings naming the changed properties of the old state vs the new state