conditional package require

[hsiaosiyuan0]

the mole's dependency scanner should support the functionality called "conditional package require"(you wouldn't search it, i name it personally)

consider below code which copied from the entry file of the famous React package:

'use strict';

if (process.env.NODE_ENV === 'production') {
  module.exports = require('./cjs/react.production.min.js');
} else {
  module.exports = require('./cjs/react.development.js');
}

bundle tools like webpack can understand the conditional require semantic in above code process.env.NODE_ENV === 'production', so there is only one of either react.production.min.js or react.development.js appears in the final dependency-graph. such ability should come with mole's dependency scanner as well

as a footnote, despite the example above uses the commonjs's package including manner require, it does not mean that condition import interpretation is meaningless in the esm situation by considering the dynamic import

[hsiaosiyuan0]

the implementation of this functionality needs to be divided into 2 parts, one for commonjs, one for esm

for the commonjs part, these steps should be taken into account:

• 1. distinguish the require calls, note the callee require should refer to the global require function, rather than bound to other values
• 2. find the conditions which may cause the require happen, the places where the conditions could appear are the IfStatement and ConditionalExpression
• 3. evaluate the conditions then select their corresponding requires

for the esm part, all the steps are same with the steps in commonjs except the first step:

1. find the import calls, no need to ensure if the callee import refers to the global import function, since the import was never a function, it's a keyword instead see import - syntax