three-way-merger



Used to figure out the minimum changes needed to be made to create a 3-way merge of dependencies (for an app's devDependencies or dependencies, e.g.).

usage

``javascript
var Merger = require('three-way-merger');

// e.g., the blueprinted package.json from the version of ember-cli we are upgrading from:
var source = {
devDependencies: {
a: '1.0',
b: '2.0',
e: '1.0',
f: '1.0'
}
};

var ours = {
devDependencies: {
a: '1.0',
// b: '2.0', // user removed dep on 'b'
c: '3.0', // and added dep on 'c'
e: '1.0',
f: '2.0' // user updated independently to latest
}
};

// e.g., the blueprinted package.json from the version of ember-cli we are upgrading to:
var theirs = {
devDependencies: {
a: '1.5', // a was bumped
b: '2.5', // b was bumped
d: '1.0', // ember-cli introduced new dep on d
// e: '1.0', // e was removed
f: '1.5' // f was bumped, but ours is newer so ignore
}
};

var result = Merger.merge({source: source, ours: ours, theirs: theirs});

console.log(result.devDependencies.add);
// [{name: 'd', version: '1.0'}] // need to add dep on d@1.0
// dep 'b' is not listed as requiring addition because user explicitly removed it from ours devDependencies

console.log(result.devDependencies.remove);
// [{name: 'e', version: '1.0'}] // need to remove dep on e@1.0

console.log(result.devDependencies.change);
// [{name: 'a', version: '1.5', fromVersion: '1.0'}] // need to update a@1.0 to a@1.5
// dep 'f' is not listed as requiring change because user explicitly updated it past theirs version

``

to do

* documentation