Lodash - Difference between extend/assign, merge and defaults functions

For whatever reasons, my brain refuse to remember the behaviors of the aforementionned utility functions to deal with objects fusion.
According to this stackoverflow issue, it seems that I'm not the only one, so I hope this cheatsheet would be useful to someone else.

Function aliases

The _.assign naming convention is favored over _.extend to be in sync with ES6.

Comparison

n = 'name', w = 'weapons' Assign Merge Defaults
{n: 'Asterix'}
{n: 'Obelix'}
{n: 'Obelix'} {n: 'Obelix'} {n: 'Asterix'}
{n: 'Asterix', w: 'glaive'}
{n: 'Obelix'}
{n: 'Obelix', w: 'glaive'} {n: 'Obelix', w: 'glaive'} {n: 'Asterix', w: 'glaive'}
{n: 'Asterix', ws: ['glaive', 'potion']}
{n: 'Obelix', ws: ['menhir']}
{n: 'Obelix', ws: ['menhir']} {n: 'Obelix', ws: ['menhir', 'potion']} {n: 'Asterix', ws: ['glaive', 'potion']}
{n: 'Asterix', ws: ['glaive', 'potion']}
{n: 'Obelix', ws: ['menhir']}
{n: 'Obelix', ws: ['menhir']} {n: 'Obelix', ws: ['menhir', 'potion']} {n: 'Asterix', ws: ['glaive', 'potion']}
{n: 'Asterix', ws: ['glaive', 'potion']}
{n: 'Obelix', ws: ['menhir']}
{n: 'Idefix', ws:['claws']}
{n: 'Idefix', ws: ['claws']} {n: 'Idefix', ws: ['claws', 'potion']} {n: 'Asterix', ws: ['glaive', 'potion']}

Cascade order

._defaults(result, projectConf, userConf, systemConf)