有条件地添加元素

/**
 * Add item to array conditionally.
 * @param {boolean} condition
 * @param {*} value new item or array of new items
 * @param {boolean} multiple use value as array of new items (for future)
 * @returns {array} array to spread
 * @example [ ...arrayAddConditionally(true, 'foo'), ...arrayAddConditionally(false, 'bar'), ...arrayAddConditionally(true, [1, 2, 3]), ...arrayAddConditionally(true, [4, 5, 6], true) ] // ['foo', [1, 2, 3], 4, 5, 6]
 */
export const arrayAddConditionally = (condition, value, multiple) => (
    condition
        ? multiple ? value : [value]
        : []
);

创建带有条件元素的数组

/**
 * Create array with conditional elements
 * @typedef {[condition: boolean, value: any, multiple: boolean]} ConditionalElement
 * @param {(ConditionalElement|*)[]} map non-array element will be added as it is, array element must allways be conditional
 * @returns {array} new array
 * @example createArrayConditionally([[true, 'foo'], [false, 'baz'], [true, [1, 2, 3]], [true, [4, 5, 6], true], {}]) // ['foo', [1,2,3], 4, 5, 6, {}]
 */
export const createArrayConditionally = (map) => (
    map.reduce((newArray, item) => {
        // add non-conditional as it is
        if (!Array.isArray(item)) {
            newArray.push(item);
        } else {
            const [condition, value, multiple] = item;
            // if multiple use value as array of new items
            if (condition) newArray.push[multiple ? 'apply' : 'call'](newArray, value);
        }
        return newArray;
    }, [])
);

替代方法:预过滤填充而不是后过滤:

const populate = function(...values) {
    return values.filter(function(el) {
        return el !== false
    });
};

console.log(populate("foo", true && "bar", false && "baz"))

返回

(2) ["foo", "bar"]

我知道这不能解决速记符号(因为无论你怎么尝试，它都不会起作用)，但它接近于那个。

如果你真的想把它作为一行，你可以使用:

const cond = true;
const myArr = ["foo"].concat(cond ? ["bar"] : []);

有条件地添加元素

/**
 * Add item to array conditionally.
 * @param {boolean} condition
 * @param {*} value new item or array of new items
 * @param {boolean} multiple use value as array of new items (for future)
 * @returns {array} array to spread
 * @example [ ...arrayAddConditionally(true, 'foo'), ...arrayAddConditionally(false, 'bar'), ...arrayAddConditionally(true, [1, 2, 3]), ...arrayAddConditionally(true, [4, 5, 6], true) ] // ['foo', [1, 2, 3], 4, 5, 6]
 */
export const arrayAddConditionally = (condition, value, multiple) => (
    condition
        ? multiple ? value : [value]
        : []
);

创建带有条件元素的数组

/**
 * Create array with conditional elements
 * @typedef {[condition: boolean, value: any, multiple: boolean]} ConditionalElement
 * @param {(ConditionalElement|*)[]} map non-array element will be added as it is, array element must allways be conditional
 * @returns {array} new array
 * @example createArrayConditionally([[true, 'foo'], [false, 'baz'], [true, [1, 2, 3]], [true, [4, 5, 6], true], {}]) // ['foo', [1,2,3], 4, 5, 6, {}]
 */
export const createArrayConditionally = (map) => (
    map.reduce((newArray, item) => {
        // add non-conditional as it is
        if (!Array.isArray(item)) {
            newArray.push(item);
        } else {
            const [condition, value, multiple] = item;
            // if multiple use value as array of new items
            if (condition) newArray.push[multiple ? 'apply' : 'call'](newArray, value);
        }
        return newArray;
    }, [])
);

当条件为false时，可以将数组展开到数组内部，以保持项数组干净。

你可以这样做:

//返回['foo'， 'bar'] Const项= [ “foo”, …真的吗?['bar']: []， …假的?['falsy']: []， ］ console.log(物品)

解释:

如你所见，三元运算符总是返回一个数组。

如果条件为真，则返回['bar']，否则返回空数组[]。

之后我们散开……结果数组(来自三元操作)和数组的项被推入到父数组。

如果没有任何数组项(当三元检查为false时)，则不会推送任何东西，这是我们的目标。

在另一个回答中，我解释了同样的想法，只是针对对象。你也可以在这里查看。

我会这样做

[
  true && 'one',
  false && 'two',
  1 === 1 && 'three',
  1 + 1 === 9 && 'four'
].filter(Boolean) // ['one', 'three']

注意，这也会删除错误的值，比如空字符串。