Changing Table of Content Format

Question

I am using the book document class, and have parts, chapters, and sections.

I set the tableofcontents to show just parts and chapters:

\setcounter{tocdepth}{0}

However, now the TOC has large spacing between all the items, and everything is bold.

Ideally, I would like the formatting to be similar to the default behaviour when there are chapters and sections.

The default behavior is:

Chapters bold and spaced; sections normal and close together.

I'd like:

Parts bold and spaced; chapters normal and close together.

Answer 1

\documentclass[]{book}

\setcounter{tocdepth}{0}

\makeatletter
\let\l@part\l@chapter
\def\l@chapter{\@dottedtocline {0}{1.5em}{2.3em}}
\makeatother

\begin{document}
\tableofcontents
\part{I should create MWEs}
\chapter{In the future I'll provide a MWE}
\chapter{I promise to provide MWEs when I ask on TeX.SX}
\part{I really should create MWEs}
\chapter{In the future I'll provide a MWE}
\chapter{I promise to provide MWEs when I ask on TeX.SX}
\part{I will accept answers}
\chapter{I will upvote answers}
\end{document}

Explanation: The macros responsible for typesetting the ToC are all of the form layer name prefixed with \l@. To put it simple \let changes the definition of the first macro-name to the second's. And \@dottedtocline is the macro responsible for typesetting those dotted ToC lines. The first argument is the tocdepth (chapter is 0) the other two are indents.