| 1 | /**
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| 2 | * When adding a new value to a list, one does not have to necessary
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| 3 | * recompute the mean of the list in linear time. They can instead use
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| 4 | * this function to compute the new mean by providing the current mean,
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| 5 | * the number of elements in the list that produced it and the new
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| 6 | * value to add.
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| 7 | *
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| 8 | * @since 2.5.0
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| 9 | * @param {number} mean current mean
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| 10 | * @param {number} n number of items in the list
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| 11 | * @param {number} newValue the added value
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| 12 | * @returns {number} the new mean
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| 13 | *
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| 14 | * @example
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| 15 | * addToMean(14, 5, 53); // => 20.5
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| 16 | */
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| 17 | function addToMean(mean, n, newValue) {
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| 18 | return mean + (newValue - mean) / (n + 1);
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| 19 | }
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| 20 |
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| 21 | export default addToMean;
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