Iterates through the container’s immediate children, calling callback for each child.

Returning false in the callback will break iteration.

This method only iterates through the container’s immediate children. If you need to recursively iterate through all the container’s descendant nodes, use Container#walk.

Unlike the for {}-cycle or Array#forEach this iterator is safe if you are mutating the array of child nodes during iteration. PostCSS will adjust the current index to match the mutations.

const root = postcss.parse('a { color: black; z-index: 1 }')
const rule = root.first

for (const decl of rule.nodes) {
  decl.cloneBefore({ prop: '-webkit-' + decl.prop })
  // Cycle will be infinite, because cloneBefore moves the current node
  // to the next index
}

rule.each(decl => {
  decl.cloneBefore({ prop: '-webkit-' + decl.prop })
  // Will be executed only for color and z-index
})