@joenoon/mobx-react-hooks/macro/createUseObserver.js

React Hooks for MobX

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
// @ts-ignore
const babel_plugin_macros_1 = require("babel-plugin-macros");
const path_1 = __importDefault(require("path"));
function createUseObserver(config) {
    return babel_plugin_macros_1.createMacro(function useObserverMacro({ references, state: { file: { opts: { filename } } }, babel: { types: t } }) {
        // transform the importSource to a relative path if its not a library
        let { importSource } = config;
        if (path_1.default.isAbsolute(importSource)) {
            importSource = `./${path_1.default.relative(path_1.default.dirname(filename), importSource)}`;
        }
        const { useObserver = [] } = references;
        useObserver.forEach((referencePath) => {
            // program is the top scope of the file
            const program = referencePath.scope.getProgramParent().path;
            const line = referencePath.getStatementParent();
            if (line.key !== 0) {
                throw new babel_plugin_macros_1.MacroError(`${path_1.default.basename(filename)}:${line.node.loc.start.line}: ` +
                    "useObserver() provided by the macro must be the first line of the FunctionComponent.");
            }
            // lineVars is the `{a, b}` in: const {a, b} = useObserver();
            const lineVars = line.node.declarations ? line.node.declarations[0].id : null;
            const lineArgs = referencePath.container.arguments;
            // get all lines in the scope that follow.  these get moved automatically
            const linesAfter = line.container.splice(line.key + 1, line.container.length - line.key - 1);
            // return a new function taking lineVars as args, containing linesAfter.
            // the name `useObserverRenderHook` is not important.
            line.insertAfter(t.returnStatement(t.callExpression(t.identifier(config.importSpecifier), [
                t.functionExpression(t.identifier("useObserverRenderHook"), lineVars ? [lineVars] : [], t.blockStatement(linesAfter), false, false),
                ...lineArgs
            ])));
            // remove the original line
            line.remove();
            // check to see if we've already added the real import line to this file
            const foundImport = program.get("body").filter((x) => {
                if (t.isImportDeclaration(x) && x.node.source.value === importSource) {
                    return (x.node.specifiers.filter((s) => s.local.name === config.importSpecifier).length > 0);
                }
                return false;
            }).length > 0;
            // if not, add it, i.e.:
            // import { importSpecifier } from importSource
            if (!foundImport) {
                program.unshiftContainer("body", t.importDeclaration([
                    t.importSpecifier(t.identifier(config.importSpecifier), t.identifier(config.importSpecifier))
                ], t.stringLiteral(importSource)));
            }
        });
    });
}
exports.createUseObserver = createUseObserver;
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