amis Low-Code Framework

The amis-formula package includes a variety of mathematical functions for numeric calculations.

Basic Arithmetic & Comparison

• ABS(num): Absolute value.
• INT(num): Rounds down to the nearest integer.
• MOD(num, divisor): Remainder of division.
• POW(base, exponent): Base raised to the power of exponent.
• SQRT(num): Square root.
• PI(): Returns the constant $\pi$.
• RAND(): Returns a random float between 0 and 1 (changes on every calculation).

Aggregation Functions

These functions can accept multiple arguments (num1, num2, ...) or a single array ([num1, num2, ...]).

• MAX(num1, ...): Returns the largest value.
• MIN(num1, ...): Returns the smallest value.
• SUM(num1, ...): Returns the sum of all values.
• AVG(num1, ...): Returns the average value.
• LARGE(array, k): Returns the $k$-th largest value in a dataset.

Rounding & Precision

• ROUND(num[, numDigits = 2]): Rounds to specified decimal places.
• FLOOR(num[, numDigits = 2]): Rounds down to specified decimal places.
• CEIL(num[, numDigits = 2]): Rounds up to specified decimal places.

Statistical & Specialized

• DEVSQ(num1, ...): Sum of squares of differences from the mean.
• AVEDEV(num1, ...): Mean absolute deviation from the arithmetic mean.
• HARMEAN(num1, ...): Harmonic mean.
• UPPERMONEY(num): Converts a number to Chinese uppercase currency characters.
• LAST(array): Returns the last element of an array.

// Examples
ABS(-5) // 5
SUM([1, 2, 3]) // 6
ROUND(3.14159, 2) // 3.14
RAND() * 100 // Random number between 0-100

amis distinguishes between two types of expressions used in properties like visibleOn or disabledOn:

1. JS Expressions: Raw JavaScript code (e.g., data.a == 1). If a value is provided in this format without ${ and } wrappers, it is treated as a JS expression. In the editor, these are displayed in a standard text input.
2. Formula Expressions: Expressions wrapped in ${ and } (e.g., ${a == 1 ? "1" : "2"}). These use the new formula syntax and are displayed using a dedicated formula editor.

Key Rules:

• The formula popup always uses formula syntax; it does not use template concatenation syntax.
• If you delete a JS expression, you must switch to the new formula editor to use formulas.
• When manually typing in a text field, if you want to use a literal $ sign without triggering formula logic, you must escape it as \$.

// JS Expression (Old syntax)
getSchemaTpl('expressionFormulaControl', {
  label: 'Old Syntax',
  name: 'var2',
  value: 'data.a == 1'
}),

// Formula Expression (New syntax)
getSchemaTpl('expressionFormulaControl', {
  label: 'New Syntax',
  name: 'var3',
  value: '\${a == 1 ? "1" : a == 2 ? "二" : "three"}'
})

The amis-formula package provides functions for string manipulation and text processing.

Extraction & Slicing

• LEFT(text, len): Returns the leftmost len characters.
• RIGHT(text, len): Returns the rightmost len characters.
• MID(text, from, len): Returns a substring starting at from with length len.
• LEN(text): Returns the length of the string.
• LENGTH(textArr): Returns an array of lengths for a collection of strings.
• TRUNCATE(text, maxLen): Truncates text to maxLen (e.g., amis.baidu.com becomes amis...).

Transformation

• LOWER(text): Converts to lowercase.
• UPPER(text): Converts to uppercase.
• UPPERFIRST(text): Capitalizes the first letter.
• CAPITALIZE(text): Converts text to title case.
• TRIM(text): Removes leading and trailing whitespace.
• REPLACE(text, search, replace): Performs a full replacement of search with replace.
• CONCATENATE(text1, text2, ...): Joins multiple strings.
• PADSTART(text, num, pad): Pads the start of a string to a target length.

Search & Logic

• CONTAINS(text, searchText): Returns true if text contains searchText.
• STARTSWITH(text, startString): Returns true if text starts with startString.
• ENDSWITH(text, endString): Returns true if text ends with endString.
• ISEMPTY(text): Returns true if the text is empty.
• SEARCH(text, search, start): Returns the position of the first match.

Formatting & Cleaning

• ESCAPE(text): HTML escapes the text.
• STRIPTAG(text): Removes HTML tags from the text.
• LINEBREAK(text): Converts newlines (\n) to HTML <br/>.
• SPLIT(text, delimiter): Splits a string into an array based on a delimiter.
• BEFORELAST(text, delimiter): Returns everything before the last occurrence of a delimiter.
• BASENAME(text): Returns the filename from a path.
• UUID(length): Generates a UUID string (default length 32).

// Examples
LEFT("hello", 2) // "he"
SPLIT("a,b,c", ",") // ["a", "b", "c"]
STRIPTAG("<b>amis</b>") // "amis"
PADSTART("6", 2, "0") // "06"