116 lines
2.4 KiB
JavaScript

import cloneDeep from "lodash/cloneDeep";
import has from "lodash/has";
import traverse from "babel-traverse";
import * as babylon from "babylon";
const FROM_TEMPLATE = new Set();
export default function(code: string, opts?: Object): Function {
// since we lazy parse the template, we get the current stack so we have the
// original stack to append if it errors when parsing
let stack;
try {
// error stack gets populated in IE only on throw
// (https://msdn.microsoft.com/en-us/library/hh699850(v=vs.94).aspx)
throw new Error();
} catch (error) {
if (error.stack) {
// error.stack does not exists in IE <= 9
stack = error.stack
.split("\n")
.slice(1)
.join("\n");
}
}
opts = Object.assign(
{
allowReturnOutsideFunction: true,
allowSuperOutsideMethod: true,
preserveComments: false,
},
opts,
);
let getAst = function() {
let ast;
try {
ast = babylon.parse(code, opts);
ast = traverse.removeProperties(ast, {
preserveComments: opts.preserveComments,
});
} catch (err) {
err.stack = `${err.stack}from\n${stack}`;
throw err;
}
getAst = function() {
return ast;
};
return ast;
};
return function(...args) {
return useTemplate(getAst(), args);
};
}
function useTemplate(ast, nodes?: Array<Object>) {
ast = cloneDeep(ast);
const { program } = ast;
if (nodes.length) {
traverse.cheap(ast, function(node) {
FROM_TEMPLATE.add(node);
});
traverse(ast, templateVisitor, null, nodes);
FROM_TEMPLATE.clear();
}
if (program.body.length > 1) {
return program.body;
} else {
return program.body[0];
}
}
const templateVisitor = {
// 360
noScope: true,
Identifier(path, args) {
const { node, parentPath } = path;
if (!FROM_TEMPLATE.has(node)) return path.skip();
let replacement;
if (has(args[0], node.name)) {
replacement = args[0][node.name];
} else if (node.name[0] === "$") {
const i = +node.name.slice(1);
if (args[i]) replacement = args[i];
}
if (parentPath.isExpressionStatement()) {
path = parentPath;
}
if (replacement === null) {
path.remove();
} else if (replacement) {
path.replaceInline(replacement);
path.skip();
}
},
exit({ node }) {
if (!node.loc) {
traverse.clearNode(node);
}
},
};