maybeTuple

Author: mbostock

src/mark.js

@@ -131,6 +131,11 @@ export function maybeZero(x, x1, x2, x3 = identity) {
   return [x1, x2];
 }
 
+// For marks that have x and y channels (e.g., cell, dot, line, text).
+export function maybeTuple(x, y) {
+  return x === undefined && y === undefined ? [first, second] : [x, y];
+}
+
 // A helper for extracting the z channel, if it is variable. Used by transforms
 // that require series, such as moving average and normalize.
 export function maybeZ({z, fill, stroke} = {}) {

src/marks/cell.js

@@ -1,4 +1,4 @@
-import {identity, first, second} from "../mark.js";
+import {identity, maybeTuple} from "../mark.js";
 import {AbstractBar} from "./bar.js";
 
 export class Cell extends AbstractBar {
@@ -20,7 +20,8 @@ export class Cell extends AbstractBar {
   }
 }
 
-export function cell(data, {x = first, y = second, ...options} = {}) {
+export function cell(data, {x, y, ...options} = {}) {
+  ([x, y] = maybeTuple(x, y));
   return new Cell(data, {...options, x, y});
 }
 

src/marks/dot.js

@@ -1,7 +1,7 @@
 import {ascending} from "d3";
 import {create} from "d3";
 import {filter, positive} from "../defined.js";
-import {Mark, identity, first, second, maybeColor, maybeNumber, title} from "../mark.js";
+import {Mark, identity, maybeColor, maybeNumber, maybeTuple, title} from "../mark.js";
 import {Style, applyDirectStyles, applyIndirectStyles, applyTransform} from "../style.js";
 
 export class Dot extends Mark {
@@ -68,7 +68,8 @@ export class Dot extends Mark {
   }
 }
 
-export function dot(data, {x = first, y = second, ...options} = {}) {
+export function dot(data, {x, y, ...options} = {}) {
+  ([x, y] = maybeTuple(x, y));
   return new Dot(data, {...options, x, y});
 }
 

src/marks/line.js

@@ -3,7 +3,7 @@ import {create} from "d3";
 import {line as shapeLine} from "d3";
 import {Curve} from "../curve.js";
 import {defined} from "../defined.js";
-import {Mark, indexOf, identity, first, second, maybeColor, titleGroup} from "../mark.js";
+import {Mark, indexOf, identity, maybeColor, maybeTuple, titleGroup} from "../mark.js";
 import {Style, applyDirectStyles, applyIndirectStyles, applyTransform} from "../style.js";
 
 export class Line extends Mark {
@@ -66,7 +66,8 @@ export class Line extends Mark {
   }
 }
 
-export function line(data, {x = first, y = second, ...options} = {}) {
+export function line(data, {x, y, ...options} = {}) {
+  ([x, y] = maybeTuple(x, y));
   return new Line(data, {...options, x, y});
 }
 

src/marks/text.js

@@ -1,7 +1,7 @@
 import {ascending} from "d3";
 import {create} from "d3";
 import {filter, nonempty} from "../defined.js";
-import {Mark, indexOf, identity, string, title, maybeColor, first, second} from "../mark.js";
+import {Mark, indexOf, identity, string, title, maybeColor, maybeTuple} from "../mark.js";
 import {Style, applyDirectStyles, applyIndirectStyles, applyAttr, applyStyle, applyTransform} from "../style.js";
 
 export class Text extends Mark {
@@ -72,7 +72,8 @@ export class Text extends Mark {
   }
 }
 
-export function text(data, {x = first, y = second, ...options} = {}) {
+export function text(data, {x, y, ...options} = {}) {
+  ([x, y] = maybeTuple(x, y));
   return new Text(data, {...options, x, y});
 }
 

src/transforms/group.js

@@ -1,6 +1,6 @@
 import {group as grouper, sort, InternSet} from "d3";
 import {defined} from "../defined.js";
-import {valueof, maybeColor, maybeTransform, maybeValue, maybeLazyChannel, lazyChannel, first, second, identity, take} from "../mark.js";
+import {valueof, maybeColor, maybeTransform, maybeValue, maybeLazyChannel, lazyChannel, first, identity, take, maybeTuple} from "../mark.js";
 
 export function groupX({x, ...options} = {}) {
   const [transform, X, y, z, fill, stroke] = group1(x, options);
@@ -84,8 +84,9 @@ function group1(x = identity, {domain, normalize, ...options} = {}) {
 
 function group2(xv, yv, {domain, normalize, ...options} = {}) {
   const {z, fill, stroke} = options;
-  const {value: x = first, domain: xdomain} = {domain, ...maybeValue(xv)};
-  const {value: y = second, domain: ydomain} = {domain, ...maybeValue(yv)};
+  let {value: x, domain: xdomain} = {domain, ...maybeValue(xv)};
+  let {value: y, domain: ydomain} = {domain, ...maybeValue(yv)};
+  ([x, y] = maybeTuple(x, y));
   const k = normalize === true ? 100 : +normalize;
   const [X, setX] = lazyChannel(x);
   const [Y, setY] = lazyChannel(y);