stripIndentWithTaggedTemplate.js

const WHITESPACE_PATTERN = /^[ \t]*(?=\S)/gm;

export function stripIndent(strings, ...expressions) {
  const resultString = strings.reduce((accumulator, part, i) => {
    return accumulator + expressions[i - 1] + part;
  });

  const indents = Math.min(
    ...resultString.match(WHITESPACE_PATTERN).map(whitespace => whitespace.length)
  );

  return resultString.split('\n').map(line => line.slice(indents)).join('\n');
}