-
Notifications
You must be signed in to change notification settings - Fork 1.5k
/
DataJoin.js
94 lines (76 loc) · 2.12 KB
/
DataJoin.js
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
import {Transform, ingest, tupleid} from 'vega-dataflow';
import {error, fastmap, inherits, isArray} from 'vega-util';
/**
* Joins a set of data elements against a set of visual items.
* @constructor
* @param {object} params - The parameters for this operator.
* @param {function(object): object} [params.item] - An item generator function.
* @param {function(object): *} [params.key] - The key field associating data and visual items.
*/
export default function DataJoin(params) {
Transform.call(this, null, params);
}
var prototype = inherits(DataJoin, Transform);
function defaultItemCreate() {
return ingest({});
}
function isExit(t) {
return t.exit;
}
prototype.transform = function(_, pulse) {
var df = pulse.dataflow,
out = pulse.fork(pulse.NO_SOURCE | pulse.NO_FIELDS),
item = _.item || defaultItemCreate,
key = _.key || tupleid,
map = this.value;
// prevent transient (e.g., hover) requests from
// cascading across marks derived from marks
if (isArray(out.encode)) {
out.encode = null;
}
if (map && (_.modified('key') || pulse.modified(key))) {
error('DataJoin does not support modified key function or fields.');
}
if (!map) {
pulse = pulse.addAll();
this.value = map = fastmap().test(isExit);
map.lookup = function(t) { return map.get(key(t)); };
}
pulse.visit(pulse.ADD, function(t) {
var k = key(t),
x = map.get(k);
if (x) {
if (x.exit) {
map.empty--;
out.add.push(x);
} else {
out.mod.push(x);
}
} else {
map.set(k, (x = item(t)));
out.add.push(x);
}
x.datum = t;
x.exit = false;
});
pulse.visit(pulse.MOD, function(t) {
var k = key(t),
x = map.get(k);
if (x) {
x.datum = t;
out.mod.push(x);
}
});
pulse.visit(pulse.REM, function(t) {
var k = key(t),
x = map.get(k);
if (t === x.datum && !x.exit) {
out.rem.push(x);
x.exit = true;
++map.empty;
}
});
if (pulse.changed(pulse.ADD_MOD)) out.modifies('datum');
if (_.clean && map.empty > df.cleanThreshold) df.runAfter(map.clean);
return out;
};