endent/src/index.ts

➡️ An ES6 string tag that makes indentation right

import dedent from "dedent";
import objectorarray from "objectorarray";
import parse from "fast-json-parse";

const ENDENT_ID = "twhZNwxI1aFG3r4";

function endent(strings: TemplateStringsArray, ...values: any[]) {
  let result = "";

  for (let i = 0; i < strings.length; i++) {
    result += strings[i];

    if (i < values.length) {
      let value = values[i];
      let isJson = false;

      if (parse(value).value) {
        value = parse(value).value;
        isJson = true;
      }

      if ((value && value[ENDENT_ID]) || isJson) {
        let rawlines = result.split("\n");
        let l = rawlines[rawlines.length - 1].search(/\S/);
        let endentation = l > 0 ? " ".repeat(l) : "";
        let valueJson = isJson
          ? JSON.stringify(value, null, 2)
          : value[ENDENT_ID];
        let valueLines = valueJson.split("\n");

        valueLines.forEach((l: string, index: number) => {
          if (index > 0) {
            result += "\n" + endentation + l;
          } else {
            result += l;
          }
        });
      } else if (typeof value === "string" && value.includes("\n")) {
        let endentations = result.match(/(?:^|\n)( *)$/);

        if (typeof value === "string") {
          let endentation = endentations ? endentations[1] : "";
          result += value
            .split("\n")
            .map((str, i) => {
              str = ENDENT_ID + str;
              return i === 0 ? str : `${endentation}${str}`;
            })
            .join("\n");
        } else {
          result += value;
        }
      } else {
        result += value;
      }
    }
  }
  result = dedent(result);
  return result.split(ENDENT_ID).join("");
}

endent.pretty = (data?: object | string | number | undefined | null) => {
  return objectorarray(data)
    ? { [ENDENT_ID]: JSON.stringify(data, null, 2) }
    : data;
};

export default endent;