Eu escrevi minha própria pequena biblioteca em torno disso, recentemente, que tenta ficar o mais próximo possível
5.1 Modelo de processamento (XSLT REC)
https://www.w3.org/TR/xslt#section-Processing-Model
quanto possível (como eu poderia de qualquer maneira), em algumas linhas de código JavaScript.
Aqui estão alguns exemplos de uso não completamente triviais ...
1. JSON para alguma marcação:
Fiddle: https://jsfiddle.net/YSharpLanguage/kj9pk8oz/10
(inspirado no Exemplo de documento D.1 (XSLT REC) https://www.w3.org/TR/xslt#section-Document-Example )
onde isso:
var D1document = {
type: "document", title: [ "Document Title" ],
"": [
{ type: "chapter", title: [ "Chapter Title" ],
"": [
{ type: "section", title: [ "Section Title" ],
"": [
{ type: "para", "": [ "This is a test." ] },
{ type: "note", "": [ "This is a note." ] }
] },
{ type: "section", title: [ "Another Section Title" ],
"": [
{ type: "para", "": [ "This is ", { emph: "another" }, " test." ] },
{ type: "note", "": [ "This is another note." ] }
] }
] }
] };
var D1toHTML = { $: [
[ [ function(node) { return node.type === "document"; } ],
function(root) {
return "<html>\r\n\
<head>\r\n\
<title>\r\n\
{title}\r\n".of(root) + "\
</title>\r\n\
</head>\r\n\
<body>\r\n\
{*}".of(root[""].through(this)) + "\
</body>\r\n\
</html>";
}
],
[ [ function(node) { return node.type === "chapter"; } ],
function(chapter) {
return " <h2>{title}</h2>\r\n".of(chapter) + "{*}".of(chapter[""].through(this));
}
],
[ [ function(node) { return node.type === "section"; } ],
function(section) {
return " <h3>{title}</h3>\r\n".of(section) + "{*}".of(section[""].through(this));
}
],
[ [ function(node) { return node.type === "para"; } ],
function(para) {
return " <p>{*}</p>\r\n".of(para[""].through(this));
}
],
[ [ function(node) { return node.type === "note"; } ],
function(note) {
return ' <p class="note"><b>NOTE: </b>{*}</p>\r\n'.of(note[""].through(this));
}
],
[ [ function(node) { return node.emph; } ],
function(emph) {
return "<em>{emph}</em>".of(emph);
}
]
] };
console.log(D1document.through(D1toHTML));
... dá:
<html>
<head>
<title>
Document Title
</title>
</head>
<body>
<h2>Chapter Title</h2>
<h3>Section Title</h3>
<p>This is a test.</p>
<p class="note"><b>NOTE: </b>This is a note.</p>
<h3>Another Section Title</h3>
<p>This is <em>another</em> test.</p>
<p class="note"><b>NOTE: </b>This is another note.</p>
</body>
</html>
e
2. JSON para JSON:
Fiddle: https://jsfiddle.net/YSharpLanguage/ppfmmu15/10
onde isso:
// (A "Company" is just an object with a "Team")
function Company(obj) {
return obj.team && Team(obj.team);
}
// (A "Team" is just a non-empty array that contains at least one "Member")
function Team(obj) {
return ({ }.toString.call(obj) === "[object Array]") &&
obj.length &&
obj.find(function(item) { return Member(item); });
}
// (A "Member" must have first and last names, and a gender)
function Member(obj) {
return obj.first && obj.last && obj.sex;
}
function Dude(obj) {
return Member(obj) && (obj.sex === "Male");
}
function Girl(obj) {
return Member(obj) && (obj.sex === "Female");
}
var data = { team: [
{ first: "John", last: "Smith", sex: "Male" },
{ first: "Vaio", last: "Sony" },
{ first: "Anna", last: "Smith", sex: "Female" },
{ first: "Peter", last: "Olsen", sex: "Male" }
] };
var TO_SOMETHING_ELSE = { $: [
[ [ Company ],
function(company) {
return { some_virtual_dom: {
the_dudes: { ul: company.team.select(Dude).through(this) },
the_grrls: { ul: company.team.select(Girl).through(this) }
} }
} ],
[ [ Member ],
function(member) {
return { li: "{first} {last} ({sex})".of(member) };
} ]
] };
console.log(JSON.stringify(data.through(TO_SOMETHING_ELSE), null, 4));
... dá:
{
"some_virtual_dom": {
"the_dudes": {
"ul": [
{
"li": "John Smith (Male)"
},
{
"li": "Peter Olsen (Male)"
}
]
},
"the_grrls": {
"ul": [
{
"li": "Anna Smith (Female)"
}
]
}
}
}
3. XSLT vs. JavaScript:
Um equivalente a JavaScript de ...
Seção 14.4 do XSLT 3.0 REC Exemplo: agrupando nós com base em valores comuns
(em: http://jsfiddle.net/YSharpLanguage/8bqcd0ey/1 )
Cf. https://www.w3.org/TR/xslt-30/#grouping-examples
Onde...
var cities = [
{ name: "Milano", country: "Italia", pop: 5 },
{ name: "Paris", country: "France", pop: 7 },
{ name: "München", country: "Deutschland", pop: 4 },
{ name: "Lyon", country: "France", pop: 2 },
{ name: "Venezia", country: "Italia", pop: 1 }
];
/*
Cf.
XSLT 3.0 REC Section 14.4
Example: Grouping Nodes based on Common Values
https://www.w3.org/TR/xslt-30/#grouping-examples
*/
var output = "<table>\r\n\
<tr>\r\n\
<th>Position</th>\r\n\
<th>Country</th>\r\n\
<th>City List</th>\r\n\
<th>Population</th>\r\n\
</tr>{*}\r\n\
</table>".of
(
cities.select().groupBy("country")(function(byCountry, index) {
var country = byCountry[0],
cities = byCountry[1].select().orderBy("name");
return "\r\n\
<tr>\r\n\
<td>{position}</td>\r\n\
<td>{country}</td>\r\n\
<td>{cities}</td>\r\n\
<td>{population}</td>\r\n\
</tr>".
of({ position: index + 1, country: country,
cities: cities.map(function(city) { return city.name; }).join(", "),
population: cities.reduce(function(sum, city) { return sum += city.pop; }, 0)
});
})
);
... dá:
<table>
<tr>
<th>Position</th>
<th>Country</th>
<th>City List</th>
<th>Population</th>
</tr>
<tr>
<td>1</td>
<td>Italia</td>
<td>Milano, Venezia</td>
<td>6</td>
</tr>
<tr>
<td>2</td>
<td>France</td>
<td>Lyon, Paris</td>
<td>9</td>
</tr>
<tr>
<td>3</td>
<td>Deutschland</td>
<td>München</td>
<td>4</td>
</tr>
</table>
4. JSONiq vs. JavaScript:
Um equivalente a JavaScript de ...
Casos de uso JSONiq Seção 1.1.2. Agrupando consultas para JSON
(em: https://jsfiddle.net/YSharpLanguage/hvo24hmk/3 )
Cf. http://jsoniq.org/docs/JSONiq-usecases/html-single/index.html#jsongrouping
Onde...
/*
1.1.2. Grouping Queries for JSON
http://jsoniq.org/docs/JSONiq-usecases/html-single/index.html#jsongrouping
*/
var sales = [
{ "product" : "broiler", "store number" : 1, "quantity" : 20 },
{ "product" : "toaster", "store number" : 2, "quantity" : 100 },
{ "product" : "toaster", "store number" : 2, "quantity" : 50 },
{ "product" : "toaster", "store number" : 3, "quantity" : 50 },
{ "product" : "blender", "store number" : 3, "quantity" : 100 },
{ "product" : "blender", "store number" : 3, "quantity" : 150 },
{ "product" : "socks", "store number" : 1, "quantity" : 500 },
{ "product" : "socks", "store number" : 2, "quantity" : 10 },
{ "product" : "shirt", "store number" : 3, "quantity" : 10 }
];
var products = [
{ "name" : "broiler", "category" : "kitchen", "price" : 100, "cost" : 70 },
{ "name" : "toaster", "category" : "kitchen", "price" : 30, "cost" : 10 },
{ "name" : "blender", "category" : "kitchen", "price" : 50, "cost" : 25 },
{ "name" : "socks", "category" : "clothes", "price" : 5, "cost" : 2 },
{ "name" : "shirt", "category" : "clothes", "price" : 10, "cost" : 3 }
];
var stores = [
{ "store number" : 1, "state" : "CA" },
{ "store number" : 2, "state" : "CA" },
{ "store number" : 3, "state" : "MA" },
{ "store number" : 4, "state" : "MA" }
];
var nestedGroupingAndAggregate = stores.select().orderBy("state").groupBy("state")
( function(byState) {
var state = byState[0],
stateStores = byState[1];
byState = { };
return (
(
byState[state] =
products.select().orderBy("category").groupBy("category")
( function(byCategory) {
var category = byCategory[0],
categoryProducts = byCategory[1],
categorySales = sales.filter(function(sale) {
return stateStores.find(function(store) { return sale["store number"] === store["store number"]; }) &&
categoryProducts.find(function(product) { return sale.product === product.name; });
});
byCategory = { };
return (
(
byCategory[category] =
categorySales.select().orderBy("product").groupBy("product")
( function(byProduct) {
var soldProduct = byProduct[0],
soldQuantities = byProduct[1];
byProduct = { };
return (
(
byProduct[soldProduct] =
soldQuantities.reduce(function(sum, sale) { return sum += sale.quantity; }, 0)
),
byProduct
);
} ) // byProduct()
),
byCategory
);
} ) // byCategory()
),
byState
);
} ); // byState()
... dá:
[
{
"CA": [
{
"clothes": [
{
"socks": 510
}
]
},
{
"kitchen": [
{
"broiler": 20
},
{
"toaster": 150
}
]
}
]
},
{
"MA": [
{
"clothes": [
{
"shirt": 10
}
]
},
{
"kitchen": [
{
"blender": 250
},
{
"toaster": 50
}
]
}
]
}
]
Também é útil superar as limitações do JSONPath wrt. consulta contra o eixo ancestral, conforme levantado por essa pergunta do SO (e certamente outros).
Por exemplo, como obter o desconto de um item de supermercado sabendo seu ID de marca, em
{
"prods": [
{
"info": {
"rate": 85
},
"grocery": [
{
"brand": "C",
"brand_id": "984"
},
{
"brand": "D",
"brand_id": "254"
}
],
"discount": "15"
},
{
"info": {
"rate": 100
},
"grocery": [
{
"brand": "A",
"brand_id": "983"
},
{
"brand": "B",
"brand_id": "253"
}
],
"discount": "20"
}
]
}
?
Uma solução possível é:
var products = {
"prods": [
{
"info": {
"rate": 85
},
"grocery": [
{
"brand": "C",
"brand_id": "984"
},
{
"brand": "D",
"brand_id": "254"
}
],
"discount": "15"
},
{
"info": {
"rate": 100
},
"grocery": [
{
"brand": "A",
"brand_id": "983"
},
{
"brand": "B",
"brand_id": "253"
}
],
"discount": "20"
}
]
};
function GroceryItem(obj) {
return (typeof obj.brand === "string") && (typeof obj.brand_id === "string");
}
// last parameter set to "true", to grab all the "GroceryItem" instances
// at any depth:
var itemsAndDiscounts = [ products ].nodeset(GroceryItem, true).
map(
function(node) {
var item = node.value, // node.value: the current "GroceryItem" (aka "$.prods[*].grocery[*]")
discount = node.parent. // node.parent: the array of "GroceryItem" (aka "$.prods[*].grocery")
parent. // node.parent.parent: the product (aka "$.prods[*]")
discount; // node.parent.parent.discount: the product discount
// finally, project into an easy-to-filter form:
return { id: item.brand_id, discount: discount };
}
),
discountOfItem983;
discountOfItem983 = itemsAndDiscounts.
filter
(
function(mapped) {
return mapped.id === "983";
}
)
[0].discount;
console.log("Discount of #983: " + discountOfItem983);
... que dá:
Discount of #983: 20
«HTH,