embedded-typescript/compiler/index.js

Type safe TypeScript templates

import { format } from "prettier";
import { trimLeadingIndentation, getLeadingIndentation, trimLaggingNewline, sanitizeString, removeFinalNewline, } from "./utils/index.js";
import { parse, isParseError } from "../parser/index.js";
const RESULT = "result";
function compile(nodes) {
    let compiled = "";
    let indent = "";
    let hasPreserveIndentation = false;
    function write(text) {
        compiled += indent + text;
    }
    nodes.forEach((node, idx) => {
        const prevNode = nodes[idx - 1];
        const nextNode = nodes[idx + 1];
        switch (node.type) {
            case "header": {
                const props = /(interface|type) Props/.test(node.content)
                    ? "Props"
                    : "unknown";
                write(`${node.content}\n\n`);
                write(`export default function (props: ${props}): string {\n`);
                indent += "  ";
                write(`let ${RESULT} = '';\n`);
                break;
            }
            case "text": {
                let content = node.content;
                // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
                if (prevNode?.type === "statement" || prevNode?.type === "header") {
                    content = trimLaggingNewline(content);
                }
                // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
                if (nextNode?.type === "statement") {
                    content = trimLeadingIndentation(content);
                }
                // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
                if (!nextNode) {
                    content = removeFinalNewline(content);
                }
                if (content) {
                    write(`${RESULT} += '${sanitizeString(content)}';\n`);
                }
                break;
            }
            case "expression": {
                // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
                const indentation = getLeadingIndentation(prevNode.content ?? "");
                if (!indentation) {
                    write(`${RESULT} += ${node.content};\n`);
                }
                else {
                    hasPreserveIndentation = true;
                    write(`${RESULT} += preserveIndentation(${node.content}, '${indentation}');\n`);
                }
                break;
            }
            case "statement": {
                write(`${node.content}\n`);
                break;
            }
            default: {
                const exhaust = node.type;
                return exhaust;
            }
        }
    });
    write(`return ${RESULT};\n`);
    indent = "";
    write(`}\n`);
    // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
    if (hasPreserveIndentation) {
        write(`\nfunction preserveIndentation(text: string, indentation: string): string {
      return text
        .split("\\n")
        .map((line, idx) => (idx === 0 ? line : indentation + line))
        .join("\\n");
    }`);
    }
    return compiled;
}
export function compiler(template, templatePath) {
    const parsed = parse(template);
    if (isParseError(parsed)) {
        return parsed;
    }
    const heading = `/*
 * THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
 *
 * Run \`npx ets\` or \`yarn ets\` to regenerate this file.
 * Source: ${templatePath}
 */
/* eslint-disable */

`;
    const file = heading + compile(parsed);
    return format(file, { parser: "typescript" });
}