Lodashcheatsheet

JS
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_.filter(list, (n) => n % 2)    // → Array
_.find(list, (n) => n % 2)      // → item
_.findLast(list, ...)           // → item

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_.at([abcd], 0); // → [ a ] - 和 list[0] 相同
_.at([abcd], [0, 1]); // → [ ab ]

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_.set(object, "users[0].name", value);
_.get(object, "users[0].name");
_.get(object, ["users", 0, "name"]);

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_.forEach(list, (item, i) => ...)
_.forEachRight(list, ...)
_.map(list, ...)

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_.every(users, (u) => u.active)  // → true|false (同 _.all)
_.any(users, ...)                // → true|false (同 _.some)

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_.chunk([abcd], 2); // → [ [ab], [cd] ]
_.compact(list);
_.fill(Array(4), "x"); // → [ 'x', 'x', 'x', 'x' ]
_.flatten;
_.flattenDeep;

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_.drop([abcdef], 2); // → [   cdef ]
_.dropRight([abcdef], 2); // → [ abcd   ]
_.take([abcdef], 2); // → [ ab     ]
_.takeRight([abcdef], 2); // → [     de ]
_.slice([abcdef], 2, 4); // → [   cd   ]

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_.initial([abcdef]); // → [ abcde  ] - dropRight(list, 1)
_.rest([abcdef]); // → [  bcdef ] - takeRight(list, 1)

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_.dropWhile(list, 'active')            // 和 filter 功能类似
_.dropWhile(list, 'active', true)
_.dropWhile(list, { active: true })
_.dropWhile(list, (n) => ...)
_.dropRightWhile(list, ...)

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_.without([abcde], b); // → [ acde ]

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_.remove(list, (n) => n % 2);

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_.first([abcdef]); // → a
_.last([abcdef]); // → f

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_.uniq();
_.difference([abc], [bc]); // → [ a    ]
_.intersection([abc], [bcd]); // → [  bc  ]
_.union([abc], [bcd]); // → [ abcd ] (unique)

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Array#concat()

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_.findIndex(list, fn);
_.findLastIndex(list, fn);

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_.sortedIndex(list, val);
_.sortedLastIndex(list, val);

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_.indexOf(list, val);

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greet = (greeting, name) => `${greeting}, ${name}!`;

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fn = _.partial(fn, "hi");
fn("joe"); // → 'hi, joe!'
fn = _.partial(fn, "joe");
fn("yo"); // → 'yo, joe!'

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_.curry(greet)("hi"); // → function(name)
_.curryRight(greet)("joe"); // → function(greet)

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_.throttle(fn);
_.debounce(fn);

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_.before(5, fn); // 只执行 5 次
_.after(5, fn); // 只执行 5 次以后的
_.once(fn); // 相当于 _.before(fn, 1)

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_.wrap(_.escape, (name) => `hi ${name}`)
// 同 `name = _.escape(name)`
_.delay(fn, 2000)
_.negate(fn)
_.memoize(fn)
_.memoize(fn, ...)

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_.capitalize("hello world"); // → 'Hello world'
_.startCase("hello_world"); // → 'Hello World'
_.snakeCase("hello world"); // → 'hello_world'
_.kebabCase("hello world"); // → 'hello-world'
_.camelCase("hello world"); // → 'helloWorld'

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_.pad("abc", 3); // → 'abc'
_.pad("abc", 8); // → '   abc  '
_.pad("abc", 8, "_-"); // → '_-abc_-_'
_.padStart("abc", 3); // → 'abc'
_.padStart("abc", 6); // → '   abc'
_.padStart("abc", 6, "_-"); // → '_-_abc'
_.padEnd("abc", 3); // → 'abc'
_.padEnd("abc", 6); // → 'abc   '
_.padEnd("abc", 6, "_-"); // → 'abc_-_'

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_.trim("  str  "); // → 'str'
_.trimLeft("  str  "); // → 'str  '
_.trimRight("  str  "); // → '  str'

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_.repeat("-", 2); // → '--'
_.deburr("déjà vu"); // → 'deja vu'
_.trunc("hello world", 5); // → 'hello...'

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_.startsWith("abc", "a"); // → true
_.endsWith("abc", "c"); // → true

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_.keys(obj);
_.values(obj);

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_([1, 2, 3])
  .reduce((total, n) => total + n)
  .map((n) => n * n)
  .tap(console.log)
  .thru((n) => n.reverse())
  .value();