Given a normalized list with component names and params like: ['user', {id: 3 }]
generates a url with a leading slash relative to the provided parentComponent.
If the optional param _aux is true, then we generate starting at an auxiliary
route boundary.
Source
Instruction generate(
List<dynamic> linkParams, List<Instruction> ancestorInstructions,
[_aux = false]) {
var params = splitAndFlattenLinkParams(linkParams);
var prevInstruction;
// The first segment should be either '.' (generate from parent) or '' (generate from root).
// When we normalize above, we strip all the slashes, './' becomes '.' and '/' becomes ''.
if (params.first == "") {
params.removeAt(0);
prevInstruction = ancestorInstructions.first;
ancestorInstructions = [];
} else {
prevInstruction = ancestorInstructions.length > 0
? ancestorInstructions.removeLast()
: null;
if (params.first == ".") {
params.removeAt(0);
} else if (params.first == "..") {
while (params.first == "..") {
if (ancestorInstructions.length <= 0) {
throw new BaseException(
'''Link "$linkParams" has too many "../" segments.''');
}
prevInstruction = ancestorInstructions.removeLast();
params = params.sublist(1);
}
} else {
// we must only peak at the link param, and not consume it
var routeName = params.first;
var parentComponentType = this._rootComponent;
var grandparentComponentType;
if (ancestorInstructions.length > 1) {
var parentComponentInstruction =
ancestorInstructions[ancestorInstructions.length - 1];
var grandComponentInstruction =
ancestorInstructions[ancestorInstructions.length - 2];
parentComponentType =
parentComponentInstruction.component.componentType;
grandparentComponentType =
grandComponentInstruction.component.componentType;
} else if (ancestorInstructions.length == 1) {
parentComponentType = ancestorInstructions[0].component.componentType;
grandparentComponentType = this._rootComponent;
}
// For a link with no leading `./`, `/`, or `../`, we look for a sibling and child.
// If both exist, we throw. Otherwise, we prefer whichever exists.
var childRouteExists = this.hasRoute(routeName, parentComponentType);
var parentRouteExists = grandparentComponentType != null &&
this.hasRoute(routeName, grandparentComponentType);
if (parentRouteExists && childRouteExists) {
var msg =
'''Link "$linkParams" is ambiguous, use "./" or "../" to disambiguate.''';
throw new BaseException(msg);
}
if (parentRouteExists) {
prevInstruction = ancestorInstructions.removeLast();
}
}
}
if (params[params.length - 1] == "") {
params.removeLast();
}
if (params.length > 0 && params[0] == "") {
params.removeAt(0);
}
if (params.length < 1) {
var msg = '''Link "$linkParams" must include a route name.''';
throw new BaseException(msg);
}
var generatedInstruction = this._generate(
params, ancestorInstructions, prevInstruction, _aux, linkParams);
// we don't clone the first (root) element
for (var i = ancestorInstructions.length - 1; i >= 0; i--) {
var ancestorInstruction = ancestorInstructions[i];
if (ancestorInstruction == null) {
break;
}
generatedInstruction =
ancestorInstruction.replaceChild(generatedInstruction);
}
return generatedInstruction;
}