Difference and use between require and import

、require And import The difference and use of (CommonJS Normative and es6 standard )

    1、import yes ES6 The Syntax Standard in is also used to load module files ,import Function can read and execute a JavaScript file , Then return to the export Command specifies the output code .export And export default Can be used to export constants 、 function 、 file 、 modular ,export There can be multiple ,export default There can only be one .

    2、require Define modules ：module Variable represents the current module , its exports Property is an external interface . adopt exports Modules can be exported from modules , Loading this module from other files is actually reading module.exports Variable , They can be variables 、 function 、 Object etc. . stay node If you use exports The system will help you convert to module.exports Of , Only the export name needs to be defined for export .

    require And import The difference between

    1,require yes CommonJS Standardized modular syntax ,import yes ECMAScript 6 Standardized modular syntax ;

    2,require Is runtime load ,import It is loaded at compile time ;

    3,require It can be written anywhere in the code ,import It can only be written at the top of the file and cannot be used in conditional statements or function scopes ;

    4,require adopt module.exports The exported value can no longer change ,import adopt export The exported value can be changed ;

    5;require adopt module.exports Exported is exports object ,import adopt export Export is the code that specifies the output ;

    6,require The properties of the module are introduced at runtime, so the performance is relatively low ,import The properties of the module are introduced during compilation, so the performance is slightly higher .