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lfreneda/collapse.js

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Last active September 6, 2017 13:17
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Collapse JOIN query result sets into a hierarchical object graph
Raw
collapse.js
'use strict';
if (!String.prototype.endsWith) {
String.prototype.endsWith = function(searchStr, Position) {
// This works much better than >= because
// it compensates for NaN:
if (!(Position < this.length))
Position = this.length;
else
Position |= 0; // round position
return this.substr(Position - searchStr.length,
searchStr.length) === searchStr;
};
}
if (!String.prototype.startsWith) {
String.prototype.startsWith = function(searchString, position) {
position = position || 0;
return this.indexOf(searchString, position) === position;
};
}
/**
* Collapses tabular result sets into a (hierarchical) object graph based on
* column nomenclature. Given a query that selects parent and child columns as
* this.id, this.val, this.children.id, this.children.val, this will return an
* array of objects in the form
*
* {id: 1, val: 'parent val', children: [{id: 11, val: 'child val'}]}
*
* and so on.
*
* @param {[type]} data Data to operate on.
* @return {[type]} Transformed object graph.
*/
module.exports = function (data) {
var parent = 'this';
var pk = 'id';
var options = {};
if (!data || data.length === 0) {
return [];
}
// console.log(data);
/* schemata defines the structural relationships of the entity-models and the fields each model consists of, and maps
* the final field names to the original columns in the query resultset.
* example: {id: parent__id, name: parent__name, children: {id: children__id, name: children__name}} */
var schemata = Object.keys(data[0]).reduce(function (acc, c) {
var tuple = c.split('.');
var entity = acc;
var name;
do {
name = tuple.shift();
if (name !== parent) {
// avoid creating a parent schema, we want that to be the root
// this almost certainly does Bad things if the graph is cyclic
// but fortunately we don't need to worry about that since the
// column name format can't define a backwards relationship
if (!entity.hasOwnProperty(name)) {
entity[name] = {};
}
entity = entity[name];
}
} while (tuple.length > 1); // walk as deep as we need to for child__grandchild__greatgrandchild__fieldname etc
entity[tuple.pop()] = c; // set {fieldname: path__to__fieldname} pair
return acc;
}, {});
/* mapping is a nested dictionary of id:entity but otherwise in the form of the final structure we're trying to build,
* effectively hashing ids to ensure we don't duplicate any entities in cases where multiple dependent tables are
* joined into the source query.
*
* example: {1: {id: 1, name: 'hi', children: {111: {id: 111, name: 'ih'}}} */
var mapping = data.reduce(function (acc, row) {
return (function build (obj, schema, parents, name) {
var opts = options[name] || {};
//var pkField = 'this.' + name + '.' + (opts.pk || pk);
var pkField = name + '.' + (opts.pk || pk);
if (parents.length) {
pkField = parents.join('.') + '.' + pkField;
// anything deeper than child.id needs to build the full column name
}
if (!pkField.startsWith(parent)) { pkField = parent + '.' + pkField; }
var id = row[pkField];
if (id === null) { // null id means this entity doesn't exist and was likely outer joined in
return;
} else if (!obj.hasOwnProperty(id)) { // this entity is new
obj[id] = {};
}
Object.keys(schema).forEach(function (c) {
if (typeof schema[c] === 'string') { // c is a field
obj[id][c] = row[schema[c]];
} else { // c is a relation
if (!obj[id].hasOwnProperty(c)) {
obj[id][c] = {}; // current object does not have relation defined, initialize it
}
// if parent isn't the root schema include that when we recurse, otherwise ignore
build(obj[id][c], schema[c], (name !== parent) ? parents.concat([name]): parents, c);
}
});
return obj;
})(acc, schemata, [], parent);
}, {});
/* Build the final graph. The structure and data already exists in mapping, but we need to transform the {id: entity} structures
* into arrays of entities (or flat objects if required).
*
* example: [{id: 1, name: 'hi', children: [{id: 111, name: 'ih'}]}] */
return (function transform(schema, map, accumulator) {
// for every id:entity pair in the current level of mapping, if the schema defines any dependent
// entities recurse and transform them, then push the current object into the accumulator and return
// console.log('map', map);
// console.log('accumulator', accumulator);
return Object.keys(map).reduce(function (acc, k) {
Object.keys(schema)
.filter(function (c) { return typeof schema[c] === 'object'; }) // just structure now
.forEach(function (c) {
// we have to init & pass the accumulator into the *next* recursion since the single
// option is defined on the child rather than the parent
// a property name ending with [] is a array otherwise is a object
var isArray = c.endsWith('[]');
if (isArray) {
map[k][c.replace('[]', '')] = transform(schema[c], map[k][c], []);
if (map[k][c]) {
// delete original key named with []
// for example: delete key named "labels[]"
delete map[k][c];
}
} else {
var value = transform(schema[c], map[k][c], {});
map[k][c] = Array.isArray(value) ? null : value;
}
// if (options[c] && options[c].sort) {
// var sort = options[c].sort;
// map[k][c].sort(function (a, b) {
// if (a[sort] > b[sort]) { return 1; }
// else if (a[sort] < b[sort]) { return -1; }
// return 0;
// });
// }
});
if (Array.isArray(accumulator)) {
acc.push(map[k]);
}
else {
acc = map[k];
}
return acc;
}, []);
})(schemata, mapping, []);
};
Raw
tests.js
'use strict';
var assert = require('chai').assert;
var collapse = require('./index');
describe('lib/collapse', function () {
describe('lib/collapse original tests cases', function() {
it('should return empty if given empty', function () {
assert.deepEqual([], collapse([]));
});
it('should collapse simple tree structures', function () {
var rows = [
{'this.id': 1, 'this.val': 'p1', 'this.children[].id': 11, 'this.children[].val': 'c1'},
{'this.id': 1, 'this.val': 'p1', 'this.children[].id': 12, 'this.children[].val': 'c2'}
];
var result = collapse(rows);
var expectedResult = [{id: 1, val: 'p1', children: [{id: 11, val: 'c1'}, {id: 12, val: 'c2'}]}];
assert.deepEqual(result, expectedResult);
});
it('should sort children if an option is specified', function () {
var rows = [
{'this.id': 1, 'this.val': 'p1', 'this.children[].id': 11, 'this.children[].val': 'c2'},
{'this.id': 1, 'this.val': 'p1', 'this.children[].id': 12, 'this.children[].val': 'c1'}
];
var result = collapse(rows);
var expectedResult = [{id: 1, val: 'p1', children: [{id: 11, val: 'c2'}, {id: 12, val: 'c1'}]}];
assert.deepEqual(result, expectedResult);
});
it('should collapse multiple children with the same parent', function () {
var rows = [
{'this.id': 1, 'this.val': 'p1', 'this.children1[].id': 11, 'this.children1[].val': 'c1', 'this.children2[].id': 21, 'this.children2[].val': 'd1'},
{'this.id': 1, 'this.val': 'p1', 'this.children1[].id': 12, 'this.children1[].val': 'c2', 'this.children2[].id': 22, 'this.children2[].val': 'd2'},
{'this.id': 1, 'this.val': 'p1', 'this.children1[].id': 12, 'this.children1[].val': 'c2', 'this.children2[].id': 23, 'this.children2[].val': 'd3'}
];
var result = collapse(rows);
var expectedResult = [{
id: 1,
val: 'p1',
children1: [{id: 11, val: 'c1'}, {id: 12, val: 'c2'}],
children2: [{id: 21, val: 'd1'}, {id: 22, val: 'd2'}, {id: 23, val: 'd3'}]
}];
assert.deepEqual(result, expectedResult);
});
it('should collapse children into other children', function () {
var rows = [
{'this.id': 1, 'this.val': 'p1', 'this.children1[].id': 11, 'this.children1[].val': 'c1', 'this.children1[].children2[].id': 21, 'this.children1[].children2[].val': 'd1'},
{'this.id': 1, 'this.val': 'p1', 'this.children1[].id': 12, 'this.children1[].val': 'c2', 'this.children1[].children2[].id': 22, 'this.children1[].children2[].val': 'd2'},
{'this.id': 1, 'this.val': 'p1', 'this.children1[].id': 12, 'this.children1[].val': 'c2', 'this.children1[].children2[].id': 23, 'this.children1[].children2[].val': 'd3'}
];
var result = collapse(rows);
var expectedResult = [{
id: 1,
val: 'p1',
children1: [{
id: 11,
val: 'c1',
children2: [{id: 21, val: 'd1'}]
}, {
id: 12,
val: 'c2',
children2: [{id: 22, val: 'd2'}, {id: 23, val: 'd3'}]
}]
}];
assert.deepEqual(result, expectedResult);
});
it('should create empty child arrays if given null children from outer joins', function () {
var rows = [
{'this.id': 1, 'this.val': 'p1', 'this.children[].id': null, 'this.children[].val': null},
{'this.id': 2, 'this.val': 'p2', 'this.children[].id': 11, 'this.children[].val': 'c1'}
];
var result = collapse(rows);
var expetedResult = [{id: 1, val: 'p1', children: []}, {id: 2, val: 'p2', children: [{id: 11, val: 'c1'}]}];
assert.deepEqual(result, expetedResult);
});
it('should collapse 1:1 relations', function () {
var rows = [
{'this.id': 1, 'this.val': 'p1', 'this.child.id': 11, 'this.child.val': 'c1'}
];
var result = collapse(rows);
var expectedResult = [{id: 1, val: 'p1', child: {id: 11, val: 'c1'}}];
assert.deepEqual(result, expectedResult);
});
it('should collapse 1:1 relations with null value', function () {
var rows = [
{'this.id': 1, 'this.val': 'p1', 'this.child.id': 11, 'this.child.val': 'c1'},
{'this.id': 2, 'this.val': 'p2', 'this.child.id': null, 'this.child.val': null},
{'this.id': 3, 'this.val': 'p3', 'this.child.id': 12, 'this.child.val': 'c2'}
];
var result = collapse(rows);
var expectedResult = [
{id: 1, val: 'p1', child: {id: 11, val: 'c1'}},
{id: 2, val: 'p2', child: null},
{id: 3, val: 'p3', child: {id: 12, val: 'c2'}}
];
assert.deepEqual(result, expectedResult);
});
it('should collapse with duplicated rows', function () {
// this dataset is 'bad' in that you're not usually going to see 100% duplicate rows unless you've really screwed up
// but it's more legible than reproducing the 'multiple children' data and tests the deduplication just the same
var rows = [
{'this.id': 1, 'this.val': 'p1', 'this.children[].id': 11, 'this.children[].val': 'c1'},
{'this.id': 1, 'this.val': 'p1', 'this.children[].id': 12, 'this.children[].val': 'c2'}, /* <---- duplicated row */
{'this.id': 1, 'this.val': 'p1', 'this.children[].id': 12, 'this.children[].val': 'c2'} /* <---- duplicated row */
];
var result = collapse(rows);
var expectedResult = [{id: 1, val: 'p1', children: [{id: 11, val: 'c1'}, {id: 12, val: 'c2'}]}];
assert.deepEqual(result, expectedResult);
});
it('should apply new parents only in the correct scope', function() {
var rows = [
{
'this.id': 1,
'this.account.id': 1,
'this.name': 'Eduardo Luiz',
'this.contact.email': 'email',
'this.contact.phone': 'phone',
'this.notes': null,
'this.archived': false,
'this.address.zipCode': 'zip',
'this.address.street': 'street',
'this.address.number': 'number',
'this.address.complement': null,
'this.address.neighborhood': null,
'this.address.city': 'Sao Paulo',
'this.address.state': 'Sao Paulo',
'this.address.coords.latitude': '1',
'this.address.coords.longitude': '2',
'this.labels[].id': '297726d0-301d-4de6-b9a4-e439b81f44ba',
'this.labels[].name': 'Contrato',
'this.labels[].color': 'yellow',
'this.labels[].type': 1
},
{
'this.id': 1,
'this.account.id': 1,
'this.name': 'Eduardo Luiz',
'this.contact.email': 'email',
'this.contact.phone': 'phone',
'this.notes': null,
'this.archived': false,
'this.address.zipCode': 'zip',
'this.address.street': 'street',
'this.address.number': 'number',
'this.address.complement': null,
'this.address.neighborhood': null,
'this.address.city': 'Sao Paulo',
'this.address.state': 'Sao Paulo',
'this.address.coords.latitude': '1',
'this.address.coords.longitude': '2',
'this.labels[].id': '1db6e07f-91e2-42fb-b65c-9a364b6bad4c',
'this.labels[].name': 'Particular',
'this.labels[].color': 'purple',
'this.labels[].type': 1
}
];
var result = collapse(rows);
var expectedResult = [{
'id': 1,
'account': {
'id': 1
},
'name': 'Eduardo Luiz',
'contact': {
'email': 'email',
'phone': 'phone'
},
'notes': null,
'archived': false,
'address': {
'zipCode': 'zip',
'street': 'street',
'number': 'number',
'complement': null,
'neighborhood': null,
'city': 'Sao Paulo',
'state': 'Sao Paulo',
'coords': {
'latitude': '1',
'longitude': '2'
}
},
'labels': [
{
'id': '297726d0-301d-4de6-b9a4-e439b81f44ba',
'name': 'Contrato',
'color': 'yellow',
'type': 1
}, {
'id': '1db6e07f-91e2-42fb-b65c-9a364b6bad4c',
'name': 'Particular',
'color': 'purple',
'type': 1
}
]
}];
assert.deepEqual(result, expectedResult);
});
});
describe('real life scenarios', function() {
it('should collapse two tasks', function () {
var rows = [
{'this.id': 1, 'this.todo': 'do task 1'},
{'this.id': 2, 'this.todo': 'do task 2'}
];
var result = collapse(rows);
var expectedResult = [
{id: 1, todo: 'do task 1'},
{id: 2, todo: 'do task 2'}
];
assert.deepEqual(result, expectedResult);
});
it('should collapse two tasks with simple customers', function () {
var rows = [
{'this.id': 1, 'this.todo': 'do task 1', 'this.customer.id': 3, 'this.customer.name': 'Luiz'},
{'this.id': 2, 'this.todo': 'do task 2', 'this.customer.id': 4, 'this.customer.name': 'Felipe'}
];
var result = collapse(rows);
var expectedResult = [
{id: 1, todo: 'do task 1', customer: {id: 3, name: 'Luiz'}},
{id: 2, todo: 'do task 2', customer: {id: 4, name: 'Felipe'}}
];
assert.deepEqual(result, expectedResult);
});
it('should collapse two tasks with customers and its address', function () {
var rows = [
{'this.id': 1, 'this.todo': 'do task 1', 'this.customer.id': 3, 'this.customer.name': 'Luiz', 'this.customer.address.street': 'Rua dos Pinheiros 383', 'this.customer.address.coords.latitude': -1, 'this.customer.address.coords.longitude': -2 },
{'this.id': 2, 'this.todo': 'do task 2', 'this.customer.id': 4, 'this.customer.name': 'Felipe', 'this.customer.address.street': 'Avenida Rebouças 130', 'this.customer.address.coords.latitude': -3, 'this.customer.address.coords.longitude': -5 }
];
var result = collapse(rows);
var expectedResult = [
{id: 1, todo: 'do task 1', customer: {id: 3, name: 'Luiz', address: { street: 'Rua dos Pinheiros 383', coords: { latitude: -1, longitude: -2 }}}},
{id: 2, todo: 'do task 2', customer: {id: 4, name: 'Felipe', address: { street: 'Avenida Rebouças 130', coords: { latitude: -3, longitude: -5 }}}}
];
assert.deepEqual(result, expectedResult);
});
it('should collapse a complete customer with address and labels', function() {
var rows = [
{
"this.id": 1,
"this.name": "Eduardo Luiz",
"this.account.id": 1,
"this.contact.email": "[email protected]",
"this.contact.phone": "11965874523",
"this.notes": null,
"this.archived": false,
"this.address.zipCode": "05422010",
"this.address.street": "Rua dos Pinheiros",
"this.address.number": "383",
"this.address.complement": null,
"this.address.neighborhood": null,
"this.address.city": "Sao Paulo",
"this.address.state": "Sao Paulo",
"this.address.coords.latitude": "1",
"this.address.coords.longitude": "2",
"this.labels[].id": "297726d0-301d-4de6-b9a4-e439b81f44ba",
"this.labels[].name": "Contrato",
"this.labels[].color": "yellow",
"this.labels[].type": 1
},
{
"this.id": 1,
"this.account.id": 1,
"this.name": "Eduardo Luiz",
"this.contact.email": "[email protected]",
"this.contact.phone": "11965874523",
"this.notes": null,
"this.archived": false,
"this.address.zipCode": "05422010",
"this.address.street": "Rua dos Pinheiros",
"this.address.number": "383",
"this.address.complement": null,
"this.address.neighborhood": null,
"this.address.city": "Sao Paulo",
"this.address.state": "Sao Paulo",
"this.address.coords.latitude": "1",
"this.address.coords.longitude": "2",
"this.labels[].id": "1db6e07f-91e2-42fb-b65c-9a364b6bad4c",
"this.labels[].name": "Particular",
"this.labels[].color": "purple",
"this.labels[].type": 1
}
];
var result = collapse(rows);
var expectedResult = [
{
"id": 1,
"account": {
"id": 1
},
"name": "Eduardo Luiz",
"contact": {
"email": "[email protected]",
"phone": "11965874523"
},
"notes": null,
"archived": false,
"address": {
"zipCode": "05422010",
"street": "Rua dos Pinheiros",
"number": "383",
"complement": null,
"neighborhood": null,
"city": "Sao Paulo",
"state": "Sao Paulo",
"coords": {
"latitude": "1",
"longitude": "2"
}
},
"labels": [
{
"id": "297726d0-301d-4de6-b9a4-e439b81f44ba",
"name": "Contrato",
"color": "yellow",
"type": 1
},
{
"id": "1db6e07f-91e2-42fb-b65c-9a364b6bad4c",
"name": "Particular",
"color": "purple",
"type": 1
}
]
}
];
assert.deepEqual(result, expectedResult);
});
it('should collapse a complete form with questions and options', function(){
var rows = [
{
"this.id": "528ad1ca-c889-46f0-b044-689e0986dab2",
"this.name": "Formulário",
"this.questions[].id": "acf9af3f-f0ce-4ac9-93c2-c18e06d887ca",
"this.questions[].type": 6,
"this.questions[].title": "Qual alimento pode ser ser transformado em código?",
"this.questions[].required": false,
"this.questions[].position": 7,
"this.questions[].options[].id": "a",
"this.questions[].options[].value": "Carne Completo",
"this.questions[].options[].position": 1
},
{
"this.id": "528ad1ca-c889-46f0-b044-689e0986dab2",
"this.name": "Formulário",
"this.questions[].id": "acf9af3f-f0ce-4ac9-93c2-c18e06d887ca",
"this.questions[].type": 6,
"this.questions[].title": "Qual alimento pode ser ser transformado em código?",
"this.questions[].required": false,
"this.questions[].position": 7,
"this.questions[].options[].id": "b",
"this.questions[].options[].value": "Café",
"this.questions[].options[].position": 2
}
];
var result = collapse(rows);
var expectedResult = [{
"id": '528ad1ca-c889-46f0-b044-689e0986dab2',
"name": 'Formulário',
"questions": [{
"id": 'acf9af3f-f0ce-4ac9-93c2-c18e06d887ca',
"type": 6,
"title": 'Qual alimento pode ser ser transformado em código?',
"required": false,
"position": 7,
"options": [
{
"id": 'a',
"value": "Carne Completo",
"position": 1
},
{
"id": 'b',
"value": "Café",
"position": 2
}
]
}]
}];
assert.deepEqual(result, expectedResult);
});
});
});
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