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module.exports = (babel) => {
const { types: t } = babel;
const GLOBAL_EXPOSURE_IDENTIFIER = 'babelPluginExportPrivates';
const HOIST_PRAGMA = 'babel-plugin-export-privates';
const identifiers = new Set();
function attachToGlobalObject(path, identifierName) {
identifiers.add(identifierName);
// Attach to global object to be exposed for exporting later.
path.insertAfter(
t.expressionStatement(
t.assignmentExpression(
'=',
t.memberExpression(
t.identifier(GLOBAL_EXPOSURE_IDENTIFIER),
t.identifier(identifierName),
),
t.identifier(identifierName),
),
),
);
}
return {
visitor: {
Program: {
enter: function(path) {
// Inject a global object for us to inject the exports into.
path.node.body.unshift(
t.variableDeclaration('const', [
t.variableDeclarator(
t.identifier(GLOBAL_EXPOSURE_IDENTIFIER),
t.objectExpression([]),
),
]),
);
},
exit: function(path) {
if (identifiers.size === 0) {
return;
}
identifiers.forEach((id) => {
const variableInGlobalScope = path.scope.hasOwnBinding(id);
// If not in global scope, declare it in global scope.
if (!variableInGlobalScope) {
path.node.body.push(
t.variableDeclaration('const', [
t.variableDeclarator(
t.identifier(id),
t.memberExpression(t.identifier(GLOBAL_EXPOSURE_IDENTIFIER), t.identifier(id)),
),
]),
);
}
});
// Add the export statements.
path.node.body.push(
t.exportNamedDeclaration(
null,
Array.from(identifiers).map((id) =>
t.exportSpecifier(t.identifier(id), t.identifier(id)),
),
),
);
},
},
'FunctionDeclaration|ClassDeclaration'(path) {
if (!path.node.leadingComments || path.node.leadingComments.length === 0) {
return;
}
const lastCommentValue =
path.node.leadingComments[path.node.leadingComments.length - 1].value;
if (lastCommentValue.includes(HOIST_PRAGMA)) {
attachToGlobalObject(path, path.node.id.name);
}
},
VariableDeclaration(path) {
if (!path.node.leadingComments || path.node.leadingComments.length === 0) {
return;
}
const lastCommentValue =
path.node.leadingComments[path.node.leadingComments.length - 1].value;
if (
!(
lastCommentValue.includes(HOIST_PRAGMA) &&
path.node.declarations &&
path.node.declarations.length > 0
)
) {
return;
}
path.node.declarations.forEach((node) => {
const id = node.id;
switch (id.type) {
case 'Identifier':
// Handle cases like: const a = 'foo';
attachToGlobalObject(path, id.name);
break;
case 'ObjectPattern':
// Handle cases like: const { a, b, c } = obj;
id.properties.forEach((property) => {
if (property.computed || !property.key) {
return;
}
attachToGlobalObject(path, property.key.name);
});
default:
break;
}
});
},
},
};
};
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