@antv/g2
Version:
the Grammar of Graphics in Javascript
89 lines • 2.67 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.combine = exports.divide = exports.unique = exports.isFlatArray = exports.lastOf = exports.firstOf = exports.transpose = exports.indexOf = exports.mapObject = void 0;
/**
* Calls a defined callback function on each key:value of a object,
* and returns a object contains the result.
*/
function mapObject(object, callbackfn) {
return Object.entries(object).reduce((obj, [key, value]) => {
obj[key] = callbackfn(value, key, object);
return obj;
}, {});
}
exports.mapObject = mapObject;
function indexOf(array) {
return array.map((_, i) => i);
}
exports.indexOf = indexOf;
/**
* @example [[1, 2, 3], ['a', 'b', 'c']] => [[1, 'a'], [2, 'b'], [3, 'c']]
*/
function transpose(matrix) {
const row = matrix.length;
const col = matrix[0].length;
// Note: new Array(col).fill(new Array(row)) is not ok!!!
// Because in this case it will fill new Array(col) with the same array: new Array(row).
const transposed = new Array(col).fill(0).map(() => new Array(row));
for (let i = 0; i < col; i++) {
for (let j = 0; j < row; j++) {
transposed[i][j] = matrix[j][i];
}
}
return transposed;
}
exports.transpose = transpose;
function firstOf(array) {
return array[0];
}
exports.firstOf = firstOf;
function lastOf(array) {
return array[array.length - 1];
}
exports.lastOf = lastOf;
function isFlatArray(array) {
return !array.some(Array.isArray);
}
exports.isFlatArray = isFlatArray;
function unique(array) {
return Array.from(new Set(array));
}
exports.unique = unique;
function divide(array, callbackfn) {
const result = [[], []];
array.forEach((item) => {
result[callbackfn(item) ? 0 : 1].push(item);
});
return result;
}
exports.divide = divide;
function comb(array, len = array.length) {
if (len === 1)
return array.map((item) => [item]);
const result = [];
for (let i = 0; i < array.length; i++) {
const rest = array.slice(i + 1);
const restComb = comb(rest, len - 1);
restComb.forEach((comb) => {
result.push([array[i], ...comb]);
});
}
return result;
}
/**
* get all combinations of two elements in an array
* @example [1, 2, 3] => [[1], [2], [3], [1, 2], [1, 3], [2, 3], [1, 2, 3]]
* @param array
* @returns
*/
function combine(array) {
if (array.length === 1)
return [array];
const result = [];
for (let i = 1; i <= array.length; i++) {
result.push(...comb(array, i));
}
return result;
}
exports.combine = combine;
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