How to use the ferrum.size function in ferrum

map(([idx, nod]) => {
      const mat = nodeStr(idx).match(re(`(?<=^|\\n)---${hspace}*\\n?$`));
      if (!mat) {
        return null;
      }
      // Offset of the actual separator line (this may deviate from the)
      const offStart = mat.index + start(idx);
      const offEnd = offStart + size(mat[0]);
      // Is there a new line or EOF before/after the separator?
      const before = Boolean(str.slice(0, offStart).match(re(`(^|(^|\\n)${hspace}*\\n)$`)));
      const after = Boolean(str.slice(offEnd).match(re(`^(${hspace}*(\\n${hspace}*(\\n|$))|$)`)));
      return {
        idx, nod, offStart, offEnd, before, after,
      };
    }),
    filter(identity),

function type(property) {
    const types = Array.isArray(property[keyword`type`]) ? property[keyword`type`] : [property[keyword`type`]];
    const realtypes = flist(filter(types, mytype => mytype !== 'null' && mytype !== undefined));
    if (property[keyword`allOf`] || property[keyword`anyOf`] || property[keyword`oneOf`] || property[keyword`not`]) {
      return text(i18n`Merged`);
    } else if (size(realtypes) === 0) {
      return text(i18n`Not specified`);
    }
    return (size(realtypes) === 1) ? inlineCode(realtypes[0]) : text(i18n`Multiple`);
  }

function nullable(property) {
    const types = Array.isArray(property[keyword`type`]) ? property[keyword`type`] : [property[keyword`type`]];
    const nulltypes = flist(filter(types, mytype => mytype === keyword`null`));
    if (size(nulltypes)) {
      return text(i18n`can be null`);
    }
    return text(i18n`cannot be null`);
  }

function type(property) {
    const types = Array.isArray(property[keyword`type`]) ? property[keyword`type`] : [property[keyword`type`]];
    const realtypes = flist(filter(types, mytype => mytype !== 'null' && mytype !== undefined));
    if (property[keyword`allOf`] || property[keyword`anyOf`] || property[keyword`oneOf`] || property[keyword`not`]) {
      return text(i18n`Merged`);
    } else if (size(realtypes) === 0) {
      return text(i18n`Not specified`);
    }
    return (size(realtypes) === 1) ? inlineCode(realtypes[0]) : text(i18n`Multiple`);
  }