@babel/plugin-transform-regenerator
Version:
Explode async and generator functions into a state machine.
100 lines (97 loc) • 2.96 kB
JavaScript
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.hoist = hoist;
var _core = require("@babel/core");
function hoist(funPath) {
_core.types.assertFunction(funPath.node);
const vars = {
__proto__: null
};
function varDeclToExpr({
node: vdec,
scope
}, includeIdentifiers) {
_core.types.assertVariableDeclaration(vdec);
const exprs = [];
vdec.declarations.forEach(function (dec) {
vars[dec.id.name] = _core.types.identifier(dec.id.name);
scope.removeBinding(dec.id.name);
if (dec.init) {
exprs.push(_core.types.assignmentExpression("=", dec.id, dec.init));
} else if (includeIdentifiers) {
exprs.push(dec.id);
}
});
if (exprs.length === 0) return null;
if (exprs.length === 1) return exprs[0];
return _core.types.sequenceExpression(exprs);
}
funPath.get("body").traverse({
VariableDeclaration: {
exit: function (path) {
const expr = varDeclToExpr(path, false);
if (expr === null) {
path.remove();
} else {
path.replaceWith(_core.types.expressionStatement(expr));
}
path.skip();
}
},
ForStatement: function (path) {
const init = path.get("init");
if (init.isVariableDeclaration()) {
const expr = varDeclToExpr(init, false);
if (expr) {
init.replaceWith(expr);
} else {
init.remove();
}
}
},
ForXStatement: function (path) {
const left = path.get("left");
if (left.isVariableDeclaration()) {
left.replaceWith(varDeclToExpr(left, true));
}
},
FunctionDeclaration: function (path) {
const node = path.node;
vars[node.id.name] = node.id;
const assignment = _core.types.expressionStatement(_core.types.assignmentExpression("=", _core.types.cloneNode(node.id), _core.types.functionExpression(path.scope.generateUidIdentifierBasedOnNode(node), node.params, node.body, node.generator, node.async)));
if (path.parentPath.isBlockStatement()) {
path.parentPath.unshiftContainer("body", assignment);
path.remove();
} else {
path.replaceWith(assignment);
}
path.scope.removeBinding(node.id.name);
path.skip();
},
FunctionExpression: function (path) {
path.skip();
},
ArrowFunctionExpression: function (path) {
path.skip();
}
});
const paramNames = {
__proto__: null
};
funPath.get("params").forEach(function (paramPath) {
const param = paramPath.node;
if (_core.types.isIdentifier(param)) {
paramNames[param.name] = param;
} else {}
});
const declarations = [];
Object.keys(vars).forEach(function (name) {
if (!hasOwnProperty.call(paramNames, name)) {
declarations.push(_core.types.variableDeclarator(vars[name], null));
}
});
return declarations;
}
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