For bar chart, by default zero values will not be plotted and will leave an empty space both in stacked and non-stacked bar charts. But if it is required to have zero values leave a hint, an option mapZeroValueTo can be configured inside data-opts to map zero values to a non-zero decimal value. See the below demonstrations:

For line charts, by default markers on zero values will tend to touch the zero axis. The behavior can be overridden by providing a mapper function. Zeros values in line charts cannot be plotted as empty spaces because a Line series is supposed to be a connected series thus zero values should be normalised to valid decimal values. The normalisation can be calculated based on values occurring before or after the zero value or by some algorithm applied on zero value's set or all sets. To allow this a mapper function can be provided by zeroValueMapperFn inside data-opts. The value of zeroValueMapperFn must be the name of a function present in global (window) scope. For each zero value this function will be called with the following parameters injected in order:

• previousValue Value occurring before the zero value or undefined if start of set.
• nextValue Value occurring next the zero value or undefined if end of set.
• index The index of the zero value in current set.
• set Current set (Array).
• sets All sets (Array of Arrays).