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Most field values are ready to be concatenated to your code string immediately.
However, some field values require extra work before they are usable.
Strings
Strings need to be quoted with either quote_ or multiline_quote_ before they
can be concatenated. These functions perform language-specific character
escaping, such as replacing ' with \' in JavaScript.
// For a single line text field.conststr=generator.quote_(block.getFieldValue('STR'));// For a multiline text field.conststr=generator.multiline_quote_(block.getFieldValue('STR'));
Variables
For the built-in variable field, getFieldValue returns a variable ID, not a
variable name. To get an actual variable name, call getVariableName in the
code generator. This returns a name that is both unique and legal. Among other
things, getVariableName:
Converts the non-ASCII characters to ASCII. This is necessary because users
can enter variable names in their own language. For example, it converts
"متغير" to "_D9_85_D8_AA_D8_BA_D9_8A_D8_B1".
Ensures variable names follow the rules set forth by programming languages.
For example, it converts spaces to underscores and adds the prefix my_ to
variable names that start with a digit.
Resolves conflicts with reserved words or other variable or function names.
For example, it converts for to for2.
For the built-in dropdown field, getFieldValue returns a language-neutral
string that might not be directly usable in code. For example, a dropdown
containing comparison operators might return 'EQUALS', 'LESS', or
'GREATER'. This can be used to look up a string that is used in code.
For the built-in checkbox field, getFieldValue returns 'TRUE' or 'FALSE'.
How you use this depends on the meaning of the checkbox. For example, you might
use it for branching while generating code.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-04-14 UTC."],[[["\u003cp\u003eFields in Blockly define user-editable values (strings, numbers, colors, etc.) for code generation.\u003c/p\u003e\n"],["\u003cp\u003eAccess field values using \u003ccode\u003egetFieldValue\u003c/code\u003e, transform them into usable strings (e.g., quoting strings, scrubbing variable names), and concatenate them into the code.\u003c/p\u003e\n"],["\u003cp\u003eUse \u003ccode\u003equote_\u003c/code\u003e or \u003ccode\u003emultiline_quote_\u003c/code\u003e to properly format string values for code generation.\u003c/p\u003e\n"],["\u003cp\u003eUse \u003ccode\u003egetVariableName\u003c/code\u003e to ensure variable names are valid and avoid conflicts in the generated code.\u003c/p\u003e\n"],["\u003cp\u003eRefer to specific block type documentation for details on returning the generated code.\u003c/p\u003e\n"]]],["Code generation with fields involves retrieving user-inputted values, such as strings or numbers, from fields. `getFieldValue` accesses these values, which vary by field type. Strings need quoting via `quote_` or `multiline_quote_`, while variables require scrubbing with `getVariableName` to ensure they are ASCII and don't clash with reserved words. Finally, the processed field value is inserted into the code string. The completed code string is returned depending on the specific type of block.\n"],null,["# Transform field values\n\nMost field values are ready to be concatenated to your code string immediately.\nHowever, some field values require extra work before they are usable.\n\nStrings\n-------\n\nStrings need to be quoted with either `quote_` or `multiline_quote_` before they\ncan be concatenated. These functions perform language-specific character\nescaping, such as replacing `'` with `\\'` in JavaScript. \n\n // For a single line text field.\n const str = generator.quote_(block.getFieldValue('STR'));\n\n // For a multiline text field.\n const str = generator.multiline_quote_(block.getFieldValue('STR'));\n\n| **Note:** the `quote_` and `multiline_quote_` methods follow an earlier naming convention with underscores, but they are public.\n\nVariables\n---------\n\nFor the built-in variable field, `getFieldValue` returns a variable ID, not a\nvariable name. To get an actual variable name, call `getVariableName` in the\ncode generator. This returns a name that is both unique and legal. Among other\nthings, `getVariableName`:\n\n- Converts the non-ASCII characters to ASCII. This is necessary because users can enter variable names in their own language. For example, it converts \"`متغير`\" to \"`_D9_85_D8_AA_D8_BA_D9_8A_D8_B1`\".\n- Ensures variable names follow the rules set forth by programming languages. For example, it converts spaces to underscores and adds the prefix `my_` to variable names that start with a digit.\n- Resolves conflicts with reserved words or other variable or function names. For example, it converts `for` to `for2`.\n\n const identifier = generator.getVariableName(block.getFieldValue('VAR'));\n\nDropdowns\n---------\n\nFor the built-in dropdown field, `getFieldValue` returns a language-neutral\nstring that might not be directly usable in code. For example, a dropdown\ncontaining comparison operators might return `'EQUALS'`, `'LESS'`, or\n`'GREATER'`. This can be used to look up a string that is used in code. \n\n const OPERATORS = {\n EQUALS: '==',\n LESS: '\u003c',\n GREATER: '\u003e',\n };\n const operator = OPERATORS[block.getFieldValue('OPERATOR')];\n\nCheckboxes\n----------\n\nFor the built-in checkbox field, `getFieldValue` returns `'TRUE'` or `'FALSE'`.\nHow you use this depends on the meaning of the checkbox. For example, you might\nuse it for branching while generating code."]]