javascript - What do factory, service and dependency injection exactly mean in angular.js -

i little confused following angular.js concepts:

• factory
• service
• dependency injection

can brief me on each 1 simple example or explanation? appreciated.

these concepts part of javascript core.

regexp factory:

console.log(regexp("[0-9]") );  console.log(regexp("[a-z]") );  console.log(regexp("[a-z]") );  console.log(regexp("[0-9a-za-z]") );

math service:

console.log(math.pi);  console.log(math.round(math.pi));  console.log(number(math.random() * 1000).tofixed());  console.log(number(math.random() * 10).toprecision(2));  console.log(math.floor(math.random() * 20) + 1);

call , apply dependency injection:

"use strict";    var foo = {      min: function min(array) {          return math.min.apply(math, array);      },        max: function max(array) {          return math.max.apply(math, array);      }  };    var bar = foo.min([1,2,3]);  var baz = foo.max([1,2,3]);    console.log("bar: " + bar);  console.log("baz: " + baz);

references

• meta programming in es6 using symbols | dotnetcurry

• john resig - fast javascript max/min

• you're using dependency injection - modern perl programming

• simple dependency injection in ruby - sebastian's blog

• sapui5: javascript coding guidelines

• functional javascript, part 3: apply, call, , arguments object