This demo shows how we can use adapters to apply custom formatting logic to legend labels based on their value.
Code
legend.valueLabels.template.adapters.add("text", function(text, target) { if (target.dataItem && (target.dataItem.get("valuePercentTotal") < 5)) { return "<5%"; } return text; });
legend.valueLabels.template.adapters.add("text", function(text, target) { if (target.dataItem && (target.dataItem.get("valuePercentTotal") < 5)) { return "<5%"; } return text; });
Example
See the Pen Applying custom formatting logic to PieChart legend values by amCharts team (@amcharts) on CodePen.