babel-plugin-transform-multiple-inheritance
Version:
babel plugin for multiple inheritance
73 lines (69 loc) • 4.5 kB
JavaScript
;
function index (babel) {
const { types: t } = babel;
return {
name: "multiple-inheritance",
visitor: {
ClassDeclaration(path) {
if (path.get('superClass').isSequenceExpression()) {
path.get('superClass').replaceWith(t.callExpression(
t.parenthesizedExpression(t.functionExpression(null, [],
t.blockStatement([
t.functionDeclaration(t.identifier('ProxySuperClass'), [],
t.blockStatement([
t.expressionStatement(t.callExpression(
t.memberExpression(t.identifier('Object'), t.identifier('assign')), [
t.thisExpression(),
...path.get('superClass').get('expressions')
.slice().reverse()
.map((path) => t.newExpression(path.node, []))
]))
])),
t.expressionStatement(
t.assignmentExpression(
'=',
t.memberExpression(t.identifier('ProxySuperClass'),
t.identifier('prototype')),
t.newExpression(
t.identifier('Proxy'), [
t.objectExpression([]),
t.objectExpression([
t.objectMethod(
'method',
t.identifier('get'),
[t.identifier('target'), t.identifier('prop')],
t.blockStatement([
t.returnStatement(
path.get('superClass').get('expressions').slice()
.reverse().reduceRight(
(acc, curr) => t.logicalExpression('||', acc,
t.memberExpression(
t.memberExpression(curr.node,
t.identifier('prototype')),
t.identifier('prop'), true)),
t.memberExpression(t.identifier('target'),
t.identifier('prop'), true))
)
])),
t.objectMethod(
'method',
t.identifier('getPrototypeOf'),
[],
t.blockStatement([
t.returnStatement(
t.memberExpression(path.get('superClass').get('expressions')[0].node,
t.identifier('prototype'))
)
])),
])
]
)
)),
t.returnStatement(t.identifier('ProxySuperClass'))
]))), []));
}
}
}
};
}
module.exports = index;