# @babel/plugin-transform-spread > Compile ES2015 spread to ES5 ## Example **In** ```js var a = ['a', 'b', 'c']; var b = [...a, 'foo']; ``` **Out** ```js var a = [ 'a', 'b', 'c' ]; var b = a.concat([ 'foo' ]); ``` ## Installation ```sh npm install --save-dev @babel/plugin-transform-spread ``` ## Usage ### Via `.babelrc` (Recommended) **.babelrc** Without options: ```json { "plugins": ["@babel/plugin-transform-spread"] } ``` With options: ```json { "plugins": [ ["@babel/plugin-transform-spread", { "loose": true }] ] } ``` ### Via CLI ```sh babel --plugins @babel/plugin-transform-spread script.js ``` ### Via Node API ```javascript require("@babel/core").transform("code", { plugins: ["@babel/plugin-transform-spread"] }); ``` ## Options ### `loose` `boolean`, defaults to `false`. In loose mode, **all** iterables are assumed to be arrays.