How to use the esutils.keyword.isIdentifierNameES6 function in esutils

const isValidIdentifier = (name) => {
  if (typeof name !== 'string' || keyword.isReservedWordES6(name, true)) {
    return false;
  } else if (name === 'await') {
    // invalid in module, valid in script; better be safe (see #4952)
    return false;
  } else {
    return keyword.isIdentifierNameES6(name);
  }
};

reduceStaticPropertyName(node) {
    if (keyword.isIdentifierNameES6(node.value)) {
      return this.t(node.value);
    }
    let n = parseFloat(node.value);
    if (n >= 0 && n.toString() === node.value) {
      return new NumberCodeRep(n);
    }
    return this.t(escapeStringLiteral(node.value));
  }

reduceStaticPropertyName(node) {
    if (keyword.isIdentifierNameES6(node.value)) {
      return t(node.value);
    }
    let n = parseFloat(node.value);
    if (n >= 0 && n.toString() === node.value) {
      return new NumberCodeRep(n);
    }
    return t(escapeStringLiteral(node.value));
  }

formatAsKey (theme) {
    const key = this.value
    if (keyword.isIdentifierNameES6(key, true) || String(parseInt(key, 10)) === key) {
      return key
    }

    const escaped = basicEscape(key)
      .replace(/\n/g, '\\n')
      .replace(/\r/g, '\\r')
      .replace(/'/g, "\\'")
    return formatUtils.wrap(theme.string.line, formatUtils.wrap(theme.string, escaped))
  }